Cisco ONS 15454 SDH E1-75 User manual

CHAPTER
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Circuits and Tunnels
Note The terms "Unidirectional Path Switched Ring" and "UPSR" may appear in Cisco literature. These terms
do not refer to using Cisco ONS 15xxx products in a unidirectional path switched ring configuration.
Rather, these terms, as well as "Path Protected Mesh Network" and "PPMN," refer generally to Cisco's
path protection feature, which may be used in any topological network configuration. Cisco does not
recommend using its path protection feature in any particular topological network configuration.
This chapter explains Cisco ONS 15454 SDH high-order and low-order circuits; low-order, data
communication channel (DCC), and IP-encapsulated tunnels; and virtual concatenated (VCAT) circuits.
To provision circuits and tunnels, refer to the Cisco ONS 15454 SDH Procedure Guide.
Chapter topics include:
•11.1 Overview, page 11-2
•11.2 Circuit Properties, page 11-3
•11.3 Cross-Connect Card Bandwidth, page 11-12
•11.4 DCC Tunnels, page 11-12
•11.5 Multiple Destinations for Unidirectional Circuits, page 11-14
•11.6 Monitor Circuits, page 11-14
•11.7 SNCP Circuits, page 11-15
•11.8 MS-SPRing Protection Channel Access Circuits, page 11-16
•11.9 MS-SPRing VC4 Squelch Table, page 11-17
•11.10 IEEE 802.17 Resilient Packet Ring Circuit Display, page 11-17
•11.11 Section and Path Trace, page 11-18
•11.12 Path Signal Label, C2 Byte, page 11-19
•11.13 Automatic Circuit Routing, page 11-19
•11.14 Manual Circuit Routing, page 11-21
•11.15 Constraint-Based Circuit Routing, page 11-25
•11.16 Virtual Concatenated Circuits, page 11-26
•11.17 Bridge and Roll, page 11-31
•11.18 Merged Circuits, page 11-36
•11.19 Reconfigured Circuits, page 11-37

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11.1 Overview
•11.20 Server Trails, page 11-37
11.1 Overview
You can create circuits across and within ONS 15454 SDH nodes and assign different attributes to
circuits. For example, you can:
•Create one-way, two-way (bidirectional), or broadcast circuits. VC low-order path tunnels
(VC_LO_PATH_TUNNEL) are automatically set to bidirectional and do not use multiple drops.
•Assign user-defined names to circuits.
•Assign different circuit sizes.
•Enable port grouping on low-order path tunnels. Three ports form a port group. For example, in one
E3-12 or one DS3i-N-12 card, four port groups are available: Ports 1 to 3 = PG1, Ports 4 to 6 = PG2,
Ports 7 to 9 = PG3, and Ports 10 to 12 = PG4.
Note Monitor circuits cannot be created on a VC3 circuit in a port group.
•Automatically or manually route VC high-order and low-order path circuits.
•Automatically route VC low-order path tunnels.
•Automatically create multiple circuits with autoranging. VC low-order path tunnels do not use
autoranging.
•Provide full protection to the circuit path.
•Provide only protected sources and destinations for circuits.
•Define a secondary circuit source or destination that allows you to interoperate an ONS 15454 SDH
subnetwork connection protection (SNCP) ring with third-party equipment SNCPs.
You can provision circuits at any of the following points:
•Before cards are installed. The ONS 15454 SDH allows you to provision slots and circuits before
installing the traffic cards. However, circuits cannot carry traffic until you install the cards and place
their ports in service. For card installation procedures and ring-related procedures, refer to the
Cisco ONS 15454 SDH Procedure Guide.
•After cards are installed, but before their ports are in service (enabled). You must put the ports in
service before circuits can carry traffic.
•After you preprovision the small form-factor pluggables (SFPs) (also called pluggable port modules
[PPMs]).
•When cards and SFPs are installed and ports are enabled. Circuits do not actually carry traffic until
the cards and SFPs are installed and the ports are in the Unlocked-enabled state; the
Locked-enabled,maintenance state; or the Unlocked-disabled,automaticInService state. Circuits
carry traffic as soon as the signal is received.

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Chapter 11 Circuits and Tunnels
11.2 Circuit Properties
11.2 Circuit Properties
The ONS 15454 SDH Circuits window, which appears in network, node, and card view, is where you can
view information about circuits. The Circuits window (Figure 11-1 on page 11-4) provides the following
information:
•Name—The name of the circuit. The circuit name can be manually assigned or automatically
generated.
•Type—Circuit types are HOP (high-order circuit), LOP (low-order circuit), VCT (VC low-order
tunnel), VCA (VC low-order aggregation point), OCHNC (dense wavelength division multiplexing
[DWDM] optical channel network connection, HOP_v (high-order virtual concatenated [VCAT]
circuit), and LOP_v (low-order VCAT circuit).
Note For OCHNC information, refer to the Cisco ONS 15454 DWDM Procedure Guide.
•Size—The circuit size. Low-order circuits are VC12, VC11 (XC-VXC-10G card only), and VC3.
High-order circuit sizes are VC4, VC4-2c, VC4-3c, VC4-4c, VC4-6c, VC4-8c, VC4-12c, VC4-16c,
and VC4-64c. OCHNC sizes are Equipped not specific, Multi-rate, 2.5 Gbps No FEC (forward error
correction), 2.5 Gbps FEC, 10 Gbps No FEC, and 10 Gbps FEC. High-order VCAT circuits are VC4
and VC4-4c. OCHNCs are DWDM only, refer to the Cisco ONS 15454 DWDM Procedure Guide for
more information. Low-order VCAT circuits are VC3 and VC12. For information on the number of
supported members for each card, see Table 11-13 on page 11-28.
•OCHNC Wlen—For OCHNCs, the wavelength provisioned for the DWDM optical channel network
connection. (DWDM only; refer to the Cisco ONS 15454 DWDM Procedure Guide for more
information).
•Direction—The circuit direction, either two-way (bidirectional) or one-way.
•OCHNC Dir—For OCHNCs, the direction of the DWDM optical channel network connection,
either east to west or west to east. (DWDM only; refer to the Cisco ONS 15454 DWDM Procedure
Guide for more information).
•Protection—The type of circuit protection. See the “11.2.4 Circuit Protection Types” section on
page 11-9.
•Status—The circuit status. See the “11.2.2 Circuit Status” section on page 11-6.
•Source—The circuit source in the format: node/slot/port “port name”/virtual container/tributary
unit group/tributary unit group/virtual container. (The port name appears in quotes.) Node and slot
always display; port “port name”/virtual container/tributary unit group/tributary unit group/virtual
container might display, depending on the source card, circuit type, and whether a name is assigned
to the port. For the STM64-XFP and MRC-12 cards, the port appears as port pluggable module
(PPM)-port. If the circuit size is a concatenated size (VC4-2c, VC4-4c, VC4-8c, etc.), VCs used in
the circuit are indicated by an ellipsis, for example, VC4-7..9 (VCs 7, 8, and 9) or VC4-10..12 (VC
10, 11, and 12).
•Destination—The circuit destination in same format (node/slot/port “port name”/virtual
container/tributary unit group/tributary unit group/virtual container) as the circuit source.
•# of VLANS—The number of VLANs used by an Ethernet circuit with end points on E-Series
Ethernet cards in single-card or multicard mode.
•# of Spans—The number of internode links that constitute the circuit. Right-clicking the column
shows a shortcut menu from which you can choose Span Details to show or hide circuit span detail.
For each node in the span, the span detail shows the node/slot/port/virtual container/tributary unit
group/tributary unit group/virtual container.

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11.2.1 Concatenated VC4 Time Slot Assignments
•State—The circuit state. See the “11.2.3 Circuit States” section on page 11-7.
The Filter button allows you to filter the circuits in network, node, or card view based on circuit name,
size, type, direction, and other attributes. In addition, you can export the Circuit window data in HTML,
comma-separated values (CSV), or tab-separated values (TSV) format using the Export command from
the File menu.
Figure 11-1 ONS 15454 SDH Circuit Window in Network View
11.2.1 Concatenated VC4 Time Slot Assignments
Table 11-1 shows the available time slot assignments for concatenated VC4s when using CTC to
provision circuits.
Table 11-1 VC4 Mapping Using CTC
Starting
VC4 VC4 VC4-2c VC4-3c VC4-4c VC4-6c VC4-8c VC4-12c VC4-16c VC4-64c
1Yes Ye s Yes Yes Yes Yes Yes Yes Yes
2Yes Ye s Yes No Yes Yes Yes No No
3Yes Ye s No No Yes Yes Yes No No
4Yes N o Yes No Yes Yes Yes No No
5Yes Ye s Yes Yes Yes Yes Yes No No
6Yes Ye s Yes No Yes Yes No No No
7Yes Ye s Yes No Yes Yes No No No

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11.2.1 Concatenated VC4 Time Slot Assignments
8YesNoNoNoYesYesNoNoNo
9Yes Ye s Yes Yes Yes Yes No No No
10 Yes Yes Yes No Yes No No No No
11 YesYesNoNoYesNoNoNoNo
12 YesNoNoNoNoNoNoNoNo
13 Yes Ye s Yes Yes Yes No Yes No No
14 YesYesYesNoNoNoNoNoNo
15 Yes Yes No No No No No No No
16 Yes No Yes No No No No No No
17 Yes Ye s Yes Yes Yes Yes Yes Yes No
18 Yes Ye s Yes No Yes Yes Yes No No
19 Yes Ye s Yes No Yes Yes Yes No No
20 YesNoNoNo YesYesYesNo No
21 Yes Ye s Yes Yes Yes Yes Yes No No
22 Yes Ye s Yes No Yes Yes No No No
23 Yes Yes No No Yes Yes No No No
24 YesNoNoNoYesYesNoNoNo
25 Yes Ye s Yes Yes Yes Yes Yes No No
26 Yes Yes Yes No Yes No No No No
27 YesYesNoNoYesNoNoNoNo
28 Yes No Yes No No No No No No
29 Yes Yes Yes Yes No No No No No
30 YesYesYesNoNoNoNoNoNo
31 Yes Yes Yes No Yes No No No No
32 YesNoNoNoNoNoNoNoNo
33 Yes Ye s Yes Yes Yes Yes Yes Yes No
34 Yes Ye s Yes No Yes Yes Yes No No
35 Yes Ye s No No Yes Yes Yes No No
36 YesNoNoNo YesYesYesNo No
37 Yes Ye s Yes Yes Yes Yes Yes No No
38 Yes Ye s Yes No Yes Yes No No No
39 Yes Yes No No Yes Yes No No No
40 Yes No Yes No Yes Yes No No No
41 Yes Ye s Yes Yes Yes Yes No No No
42 Yes Yes Yes No Yes No No No No
Table 11-1 VC4 Mapping Using CTC (continued)
Starting
VC4 VC4 VC4-2c VC4-3c VC4-4c VC4-6c VC4-8c VC4-12c VC4-16c VC4-64c

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11.2.2 Circuit Status
11.2.2 Circuit Status
The circuit statuses that appear in the Circuit window Status column are generated by CTC based on
conditions along the circuit path. Table 11-2 shows the statuses that can appear in the Status column.
43 Yes Yes Yes No Yes No No No No
44 YesNoNoNoNoNoNoNoNo
45 Yes Yes Yes Yes No No No No No
46 YesYesYesNoNoNoNoNoNo
47 Yes Yes No No No No No No No
48 YesNoNoNoNoNoNoNoNo
49 Yes Ye s Yes Yes Yes Yes Yes Yes No
50 Yes Ye s Yes No Yes Yes Yes No No
51 Yes Ye s No No Yes Yes Yes No No
52 Yes N o Yes No Yes Yes Yes No No
53 Yes Ye s Yes Yes Yes Yes Yes No No
54 Yes Ye s Yes No Yes Yes No No No
55 Yes Ye s Yes No Yes Yes No No No
56 YesNoNoNoYesYesNoNoNo
57 Yes Ye s Yes Yes Yes Yes No No No
58 Yes Yes Yes No Yes No No No No
59 YesYesNoNoYesNoNoNoNo
60 YesNoNoNoNoNoNoNoNo
61 Yes Yes Yes Yes No No No No No
62 YesYesYesNoNoNoNoNoNo
63 Yes Yes No No No No No No No
64 YesNoNoNoNoNoNoNoNo
Table 11-1 VC4 Mapping Using CTC (continued)
Starting
VC4 VC4 VC4-2c VC4-3c VC4-4c VC4-6c VC4-8c VC4-12c VC4-16c VC4-64c
Table 11-2 ONS 15454 SDH Circuit Status
Status Definition/Activity
CREATING CTC is creating a circuit.
DISCOVERED CTC created a circuit. All components are in place and a complete path
exists from circuit source to destination.
DELETING CTC is deleting a circuit.

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11.2.3 Circuit States
11.2.3 Circuit States
The circuit service state is an aggregate of the cross-connect states within the circuit.
•If all cross-connects in a circuit are in the Unlocked-enabled service state, the circuit service state
is Unlocked.
•If all cross-connects in a circuit are in a Locked state (such as Locked-enabled,maintenance;
Unlocked-disabled,automaticInService; or Locked-enabled,disabled service state) or the
Unlocked-disabled,automaticInService state, the circuit service state is Locked.
PARTIAL A CTC-created circuit is missing a cross-connect or network span, a
complete path from source to destination(s) does not exist, or an alarm
interface panel (AIP) change occurred on one of the circuit nodes and
the circuit is in need of repair. (AIPs store the node MAC address.)
In CTC, circuits are represented using cross-connects and network
spans. If a network span is missing from a circuit, the circuit status is
PARTIAL. However, a PARTIAL status does not necessarily mean a
circuit traffic failure has occurred, because traffic might flow on a
protect path.
Network spans are in one of two states: up or down. On CTC circuit
and network maps, up spans appear as green lines, and down spans
appear as gray lines. If a failure occurs on a network span during a
CTC session, the span remains on the network map but its color
changes to gray to indicate that the span is down. If you restart your
CTC session while the failure is active, the new CTC session cannot
discover the span and its span line does not appear on the network map.
Subsequently, circuits routed on a network span that goes down appear
as DISCOVERED during the current CTC session, but appear as
PARTIAL to users who log in after the span failure.
DISCOVERED_TL1 A TL1-created circuit or a TL1-like, CTC-created circuit is complete.
A complete path from source to destination(s) exists.
PARTIAL_TL1 A TL1-created circuit or a TL1-like, CTC-created circuit is missing a
cross-connect or circuit span (network link), and a complete path from
source to destination does not exist.
CONVERSION_PENDING An existing circuit in a topology upgrade is set to this status. The
circuit returns to the DISCOVERED status when the in-service
topology upgrade is complete. For more information about in-service
topology upgrades, see Chapter 12, “SDH Topologies and Upgrades.”
PENDING_MERGE Any new circuits created to represent an alternate path in a topology
upgrade are set to this status to indicate that it is a temporary circuit.
These circuits can be deleted if an in-service topology upgrade fails.
For more information about in-service topology upgrades, see
Chapter 12, “SDH Topologies and Upgrades.”
DROP_PENDING A circuit is set to this status when a new circuit drop is being added.
Table 11-2 ONS 15454 SDH Circuit Status (continued)
Status Definition/Activity

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11.2.3 Circuit States
•Partial is appended to the Locked circuit service state when circuit cross-connects state are mixed
and not all in the Unlocked-enabled service state. The Locked-partial state can occur during
automatic or manual transitions between states. The Locked-partial service state can appear during
a manual transition caused by an abnormal event such as a CTC crash or communication error, or if
one of the cross-connects could not be changed. Refer to the Cisco ONS 15454 SDH
Troubleshooting Guide for troubleshooting procedures. The Locked-partial circuit state does not
apply to OCHNC circuit types.
You can assign a state to circuit cross-connects at two points:
•During circuit creation, you can set the state on the Create Circuit wizard.
•After circuit creation, you can change a circuit state in the Edit Circuit window or from the
Tools > Circuits > Set Circuit State menu.
Note After you have created an initial circuit in a CTC session, the subsequent circuit states default to the
circuit state of the initial circuit, regardless of which nodes in the network the circuits traverse or the
node.ckt.state default setting.
During circuit creation, you can apply a service state to the drop ports in a circuit. You cannot transition
a port from the Unlocked-enabled service state to the Locked-enabled,disabled state. You must first
transition the port to the Locked-enabled,maintenance state before changing it to the
Locked-enabled,disabled state. For more information about port service state transitions, see
Appendix B, “Administrative and Service States.”
Circuits do not use the soak timer, but ports do. The soak period is the amount of time that the port
remains in the Unlocked-disabled,automaticInService service state after a signal is continuously
received. When the cross-connects in a circuit are in the Unlocked-disabled,automaticInService service
state, the ONS 15454 SDH monitors the cross-connects for an error-free signal. It changes the state of
the circuit from Locked to Unlocked or to Locked-partial as each cross-connect assigned to the circuit
path is completed. This allows you to provision a circuit using TL1, verify its path continuity, and
prepare the port to go into service when it receives an error-free signal for the time specified in the port
soak timer.
To find the remaining port soak time, choose the Maintenance > AINS Soak tabs in card view and click
the Retrieve button. If the port is in the Unlocked-disabled,automaticInService state and has a good
signal, the Time Until IS column shows the soak count down status. If the port is
Unlocked-disabled,automaticInService and has a bad signal, the Time Until IS column indicates that the
signal is bad. You must click the Retrieve button to obtain the latest time value.
Note Although ML-Series cards do not use the Telcordia GR-1093-CORE state model, you can also set a soak
timer for ML-Series cards ports. The soak period is the amount of time that the ML-Series port remains
in the Down state after an error-free signal is continuously received before changing to the Up state. To
find the remaining port soak time, choose the Maintenance > Ether/POS Port Soak tabs in ML-Series
card view and click the Retrieve button.
For more information about cross-connect states, see Appendix B, “Administrative and Service States.”

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11.2.4 Circuit Protection Types
11.2.4 Circuit Protection Types
The Protection column in the Circuit window shows the card (line) and SDH topology (path) protection
used for the entire circuit path. Table 11-3 shows the protection type indicators that appear in this
column.
11.2.5 Circuit Information in the Edit Circuit Window
You can edit a selected circuit using the Edit button on the Circuits window. The tabs that appear depend
on the circuit chosen:
•General—Displays general circuit information and allows you to edit the circuit name.
•Drops—Allows you to add a drop to a unidirectional circuit. For more information, see the
“11.5 Multiple Destinations for Unidirectional Circuits” section on page 11-14.
Table 11-3 Circuit Protection Types
Protection Type Description
1+1 The circuit is protected by a 1+1 protection group.
2F MS-SPRing The circuit is protected by a two-fiber MS-SPRing.
4F MS-SPRing The circuit is protected by a four-fiber MS-SPRing.
2F-PCA The circuit is routed on a protection channel access (PCA) path on a two-fiber
MS-SPRing; PCA circuits are unprotected.
4F-PCA The circuit is routed on a PCA path on a four-fiber MS-SPRing; PCA circuits are
unprotected.
DRI The circuit is protected by a dual-ring interconnection.
MS-SPRing The circuit is protected by both a two-fiber and a four-fiber MS-SPRing.
N/A A circuit with connections on the same node is not protected.
PCA The circuit is routed on a PCA path on both two-fiber and four-fiber MS-SPRings;
PCA circuits are unprotected.
Protected The circuit is protected by diverse SDH topologies, for example, an MS-SPRing and
an SNCP, or an SNCP and a 1+1 protection group.
SNCP The circuit is protected by an SNCP.
SPLITTER The circuit is protected by the protect transponder (TXPP_MR_2.5G) splitter
protection. For splitter information, refer to the Cisco ONS 15454 DWDM
Installation and Operations Guide.
Unknown A circuit has a source and destination on different nodes and communication is
down between the nodes. This protection type appears if not all circuit components
are known.
Unprot (black) A circuit with a source and destination on different nodes is not protected.
Unprot (red) A circuit created as a fully protected circuit is no longer protected due to a system
change, such as removal of a MS-SPRing or 1+1 protection group.
Y-Cable The circuit is protected by a transponder or muxponder card Y-cable protection
group. For more information, refer to the Cisco ONS 15454 DWDM Installation and
Operations Guide.

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11.2.5 Circuit Information in the Edit Circuit Window
•Monitors—Displays possible monitor sources and allows you to create a monitor circuit. For more
information, see the “11.6 Monitor Circuits” section on page 11-14.
•SNCP Selectors—Allows you to change SNCP selectors. For more information, see the
“11.7 SNCP Circuits” section on page 11-15.
•SNCP Switch Counts—Allows you to change SNCP switch protection paths. For more information,
see the “11.7 SNCP Circuits” section on page 11-15.
•State—Allows you to edit cross-connect service states.
•Merge—Allows you to merge aligned circuits. For more information, see the “11.18 Merged
Circuits” section on page 11-36.
Using the Export command from the File menu, you can export data from the SNCP Selectors, SNCP
Switch Counts, State, and Merge tabs in HTML, comma-separated values (CSV), or tab-separated values
(TSV) format.
The Show Detailed Map checkbox in the Edit Circuit window updates the graphical view of the circuit
to show more detailed routing information, such as:
•Circuit direction (unidirectional/bidirectional)
•The nodes, VC4s, VC3/TUG3, TUG2s, VC12s, and VC11s through which the circuit passes,
including slots and port numbers
•The circuit source and destination points
•Open Shortest Path First (OSPF) area IDs
•Link protection (SNCP, unprotected, MS-SPRing, 1+1) and bandwidth (STM-N)
For MS-SPRings, the detailed map shows the number of MS-SPRing fibers and the MS-SPRing ring ID.
For SNCP rings, the map shows the active and standby paths from circuit source to destination, and it
also shows the working and protect paths. Selectors appear as pentagons on the detailed circuit map. The
map indicates nodes set up as dual-ring interconnect nodes. For VCAT circuits, the detailed map is not
available for an entire VCAT circuit. However, you can view the detailed map to view the circuit route
for each individual member.
You can also view alarms and states on the circuit map, including:
•Alarm states of nodes on the circuit route
•Number of alarms on each node organized by severity
•Port service states on the circuit route
•Alarm state/color of the most severe alarm on the port
•Loopbacks
•Path trace states
•Path selectors states
For example, in an SNCP, the working path is indicated by a green, bidirectional arrow, and the protect
path is indicated by a purple, bidirectional arrow. Source and destination ports are shown as circles with
an S and a D. Port service states are indicated by colors, shown in Table 11-4.
Table 11-4 Port State Color Indicators
Port Color Service State
Green Unlocked-enabled
Gray Locked-enabled,disabled

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11.2.5 Circuit Information in the Edit Circuit Window
A notation within or by the squares or selector pentagons on each node indicates switches and loopbacks,
including:
•F = Force switch
•M = Manual switch
•L = Lockout switch
•Arrow = Facility (outward) or terminal (inward) loopback
Figure 11-2 shows an example of a 2F-PCA circuit with a card in terminal loopback in the Edit Circuits
window.
Figure 11-2 Terminal Loopback in the Edit Circuits Window
Move the mouse cursor over nodes, ports, and spans to see tooltips with information including the
number of alarms on a node (organized by severity), port service state, and the protection topology.
Right-click a node, port, or span on the detailed circuit map to initiate certain circuit actions:
•Right-click a unidirectional circuit destination node to add a drop to the circuit.
•Right-click a port containing a path trace capable card to initiate the path trace.
•Right-click an SNCP span to change the state of the path selectors in the SNCP circuit.
Violet Unlocked-disabled,automaticInService
Blue (Cyan) Locked-enabled,maintenance
Table 11-4 Port State Color Indicators (continued)
Port Color Service State

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11.3 Cross-Connect Card Bandwidth
11.3 Cross-Connect Card Bandwidth
The XC-VXL-10G, XC-VXL-2.5G, and XC-VXC-10G cards support both low-order and high-order
circuits, although only the XC-VXC-10G card supports VC-11 (low-order) circuits. The XC-VXL-10G
and XC-VXL-2.5G cards manage up to 192 bidirectional STM-1 cross-connects, 192 bidirectional E-3
or DS-3 cross-connects, or 1008 bidirectional E-1 cross-connects. The XC-VXC-10G card manages up
to 576 bidirectional STM-1 cross-connects, 576 bidirectional E-3 or DS-3 cross-connects, or 1344
bidirectional E-1 cross-connects.
The XC-VXL-10G, XC-VXL-2.5G, and XC-VXC-10G cards work with the TCC2/TCC2P card to
maintain connections and set up cross-connects within the node. You can create circuits using CTC.
Note Chapter 2, “Common Control Cards,” contains detailed specifications of the XC-VXL-10G,
XC-VXL-2.5G, and XC-VXC-10G cards.
11.4 DCC Tunnels
SDH provides four DCCs for network element operation, administration, maintenance, and
provisioning: one on the SDH regenerator section layer (RS-DCC) and three on the SDH multiplex
section layer, also called multiplex-section DCC (MS-DCC). A regenerator-section DCC (RS-DCC) and
multiplex-section DCC (MS-DCC) each provide 192 Kbps of bandwidth per channel. The aggregate
bandwidth of the three RS-DCCs is 576 Kbps. When multiple DCC channels exist between two
neighboring nodes, the ONS 15454 SDH balances traffic over the existing DCC channels. You can
tunnel third-party SDH equipment across ONS 15454 SDH networks using one of two tunneling
methods, a traditional DCC tunnel or an IP-encapsulated tunnel.
11.4.1 Traditional DCC Tunnels
In traditional DCC tunnels, the ONS 15454 SDH uses RS-DCC for inter-ONS-15454-SDH data
communications. It does not use the multiplex section DCCs; therefore, the MS-DCCs are available to
tunnel DCCs from third-party equipment across ONS 15454 SDH networks. If D4 through D12 are used
as data DCCs, they cannot be used for DCC tunneling.
A traditional DCC tunnel endpoint is defined by slot, port, and DCC, where DCC can be either the
RS-DCC, Tunnel 1, Tunnel 2, or Tunnel 3. You can link an RS-DCC to a MS-DCC (Tunnel 1, Tunnel 2,
or Tunnel 3) and a MS-DCC to an RS-DCC. You can also link MS-DCCs to MS-DCCs and link
RS-DCCs to RS-DCCs. To create a DCC tunnel, you connect the tunnel end points from one
ONS 15454 SDH STM-N port to another. Cisco recommends a maximum of 84 DCC tunnel connections
for an ONS 15454 SDH. Table 11-5 shows the DCC tunnels that you can create.
Ta b l e 11- 5 D C C Tu n n e l s
DCC SDH Layer SDH Bytes
STM-1 STM-4,
STM-16,
STM-644 Ports 8 Ports
RS-DCC Regenerator Section D1 to D3 Yes Yes Yes
Tunnel 1 Multiplex Section D4 to D6 No Yes Yes

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11.4.1 Traditional DCC Tunnels
Figure 11-3 shows a DCC tunnel example. Third-party equipment is connected to STM-1 cards at
Node 1/Slot 3/Port 1 and Node 3/Slot 3/Port 1. Each ONS 15454 SDH node is connected by STM-16
trunk (span) cards. In the example, three tunnel connections are created, one at Node 1 (STM-1 to
STM-16), one at Node 2 (STM-16 to STM-16), and one at Node 3 (STM-16 to STM-1).
Note A DCC does not function on a mixed network of ONS 15454 SDH nodes and ONS 15454 nodes. DCC
tunneling is required for ONS 15454 SDH nodes transporting data through ONS 15454 nodes.
Figure 11-3 Traditional DCC Tunnel
When you create DCC tunnels, keep the following guidelines in mind:
•Each ONS 15454 SDH can have up to 84 DCC tunnel connections.
•Each ONS 15454 SDH can have up to 84 RS-DCC terminations.
•An RS-DCC that is terminated cannot be used as a DCC tunnel endpoint.
•An RS-DCC that is used as a DCC tunnel endpoint cannot be terminated.
•All DCC tunnel connections are bidirectional.
Note An MS-DCC cannot be used for tunneling if a data DCC is assigned.
Tunnel 2 Multiplex Section D7 to D9 No Yes Yes
Tunnel 3 Multiplex Section D10 to D12 No Yes Yes
Ta b l e 11- 5 D C C Tu n n e l s
DCC SDH Layer SDH Bytes
STM-1 STM-4,
STM-16,
STM-644 Ports 8 Ports
Third party
equipment
Link 1
From (A)
Slot 3 (STM-1)
Port 1, RSDCC
To (B)
Slot 13 (STM-16)
Port 1, Tunnel 1
Node 1
71676
Third party
equipment
Link 2
From (A)
Slot 12 (STM-16)
Port 1, Tunnel 1
To (B)
Slot 13 (STM-16)
Port 1, Tunnel 1
Node 2
Link 3
From (A)
Slot 12 (STM-16)
Port 1, Tunnel 1
To (B)
Slot 3 (STM-1)
Port 1, RSDCC
Node 3

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11.4.2 IP-Encapsulated Tunnels
11.4.2 IP-Encapsulated Tunnels
An IP-encapsulated tunnel puts an RS-DCC in an IP packet at a source node and dynamically routes the
packet to a destination node. A traditional DCC tunnel is configured as one dedicated path across a
network and does not provide a failure recovery mechanism if the path is down. An IP-encapsulated
tunnel is a virtual path, which adds protection when traffic travels between different networks.
IP-encapsulated tunneling has the potential of flooding the DCC network with traffic resulting in a
degradation of performance for CTC. The data originating from an IP tunnel can be throttled to a
user-specified rate, which is a percentage of the total RS-DCC bandwidth.
Each ONS 15454 SDH supports up to ten IP-encapsulated tunnels. You can convert a traditional DCC
tunnel to an IP-encapsulated tunnel or an IP-encapsulated tunnel to a traditional DCC tunnel. Only
tunnels in the DISCOVERED status can be converted.
Caution Converting from one tunnel type to the other is service-affecting.
11.5 Multiple Destinations for Unidirectional Circuits
Unidirectional circuits can have multiple destinations for use in broadcast circuit schemes. In broadcast
scenarios, one source transmits traffic to multiple destinations, but traffic is not returned back to the
source. When you create a unidirectional circuit, the card that does have its receive (Rx) input terminated
with a valid input signal generates a loss of signal (LOS) alarm. To mask the alarm, create an alarm
profile suppressing the LOS alarm and apply it to the port that does not have its Rx input terminated.
11.6 Monitor Circuits
Monitor circuits are secondary circuits that monitor traffic on primary bidirectional circuits. Monitor
circuits can be created on E1 or STM-N cards. Figure 11-4 shows an example of a monitor circuit. At
Node 1, a VC4 is dropped from Port 1 of an STM-1 card. To monitor the VC4 traffic, test equipment is
plugged into Port 2 of the STM-1 card and a monitor circuit to Port 2 is provisioned in CTC. Circuit
monitors are one-way. The monitor circuit in Figure 11-4 is used to monitor VC4 traffic received by
Port 1 of the STM-1 card.
Figure 11-4 VC4 Monitor Circuit Received at an STM-1 Port
Note Monitor circuits cannot be used with Ethernet circuits.
STM-1 STM-N
XC
ONS 15454 SDH
Node 1
STM-N STM-N
XC
ONS 15454 SDH
Node 2
VC4 Drop
VC4 Monitor
Test Set
Port 1
Port 2
Class 5
Switch
71678

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11.7 SNCP Circuits
11.7 SNCP Circuits
Use the Edit Circuits window to change SNCP selectors and switch protection paths. In the SNCP
Selectors subtab on the Edit Circuits window, you can:
•View the SNCP circuit’s working and protection paths.
•Edit the reversion time.
•Set the hold-off timer.
•Edit the Signal Fail (SF)/Signal Degrade (SD) bit error rate (BER) thresholds.
Note On the SNCP Selectors tab, the SF Ber Level and SD Ber Level columns display “N/A” for those nodes
that do not support VC low-order signal BER monitoring. In Software Release 6.0, only the
Cisco ONS 15310-CL supports VC low-order signal BER monitoring.
On the SNCP Switch Counts subtab, you can:
•Perform maintenance switches on the circuit selector.
•View switch counts for the selectors.
11.7.1 Open-Ended SNCP Circuits
If ONS 15454 SDH nodes are connected to a third-party network, you can create an open-ended SNCP
circuit to route a circuit through it. To do this, you create three circuits. One circuit is created on the
source ONS 15454 SDH network. This circuit has one source and two destinations, one at each
ONS 15454 SDH that is connected to the third-party network. The second circuit is created on the
third-party network so that the circuit travels across the network on two paths to the ONS 15454 SDH
nodes. That circuit routes the two circuit signals across the network to ONS 15454 SDH nodes that are
connected to the network on other side. At the destination node network, the third circuit is created with
two sources, one at each node connected to the third-party network. A selector at the destination node
chooses between the two signals that arrive at the node, similar to a regular SNCP circuit.
11.7.2 Go-and-Return SNCP Routing
The go-and-return SNCP routing option allows you to route the SNCP working path on one fiber pair
and the protect path on a separate fiber pair (Figure 11-5). The working path will always be the shortest
path. If a fault occurs, neither the working fibers nor the protection fibers are affected. This feature only
applies to bidirectional SNCP circuits. The go-and-return option appears on the Circuit Attributes panel
of the Circuit Creation wizard.

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11.8 MS-SPRing Protection Channel Access Circuits
Figure 11-5 SNCP Go-and-Return Routing
11.8 MS-SPRing Protection Channel Access Circuits
You can provision circuits to carry traffic on MS-SPRing protection channels when conditions are fault
free. Traffic routed on MS-SPRing PCA circuits, called extra traffic, has lower priority than the traffic
on the working channels and has no means for protection. During ring or span switches, PCA circuits
are preempted and squelched. For example, in a two-fiber STM-16 MS-SPRing, STMs 9 to 16 can carry
extra traffic when no ring switches are active, but PCA circuits on these STMs are preempted when a
ring switch occurs. When the conditions that caused the ring switch are remedied and the ring switch is
removed, PCA circuits are restored if the MS-SPRing is provisioned as revertive.
Provisioning traffic on MS-SPRing protection channels is performed during circuit provisioning. The
Protection Channel Access check box appears whenever Fully Protected Path is unchecked on the circuit
creation wizard. Refer to the Cisco ONS 15454 SDH Procedure Guide for more information. When
provisioning PCA circuits, two considerations are important:
•If MS-SPRings are provisioned as nonrevertive, PCA circuits are not restored automatically after a
ring or span switch. You must switch the MS-SPRing manually.
•PCA circuits are routed on working channels when you upgrade a MS-SPRing from a two-fiber to
a four-fiber or from one STM-N speed to a higher STM-N speed. For example, if you upgrade a
two-fiber STM-16 MS-SPRing to an STM-64, STMs 9 to 16 on the STM-16 MS-SPRing become
working channels on the STM-64 MS-SPRing.
Node B
Go and Return working connection
Go and Return protecting connection
Node A
96953
Any network Any network

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11.9 MS-SPRing VC4 Squelch Table
11.9 MS-SPRing VC4 Squelch Table
MS-SPRing VC4 squelch tables show VC4s that will be squelched for every isolated node.
The MS-SPRing Squelch Table window displays the following information:
•VC4 Number—Shows the MS-SPRing VC4 numbers. For two-fiber MS-SPRings, the number of
VC4s is half the MS-SPRing OC-N, for example, an STM-16 MS-SPRing squelch table will show
8 VC4s. For four-fiber MS-SPRings, the number of VC4s in the table is the same as the MS-SPRing
STM-N.
•West Source—If traffic is received by the node on its west span, the MS-SPRing node ID of the
source appears. (To view the MS-SPRing node IDs for all nodes in the ring, click the Ring Map
button.)
•West Dest—If traffic is sent on the node’s west span, the MS-SPRing node ID of the destination
appears.
•East Source—If traffic is received by the node on its east span, the MS-SPRing node ID of the source
appears.
•East Dest—If traffic is sent on the node’s east span, the MS-SPRing node ID of the destination
appears.
Note MS-SPRing squelching is performed on VC4s that carry VC4 circuits only.
11.10 IEEE 802.17 Resilient Packet Ring Circuit Display
Resilient Packet Ring (RPR), as described in IEEE 802.17, is a metropolitan area network (MAN)
technology supporting data transfer among stations interconnected in a dual-ring configuration. The
IEEE 802.17b spatially-aware sublayer amendment is not yet ratified but is expected to add support for
bridging to IEEE 802.17. Since the amendment is not yet ratified, no equipment is currently
IEEE 802.17b compliant. The RPR-IEEE for ONS 15454 ML-Series cards is based on the expected
IEEE 802.17b-based standard.
For more information about IEEE 802.17 RPR, refer to the Cisco ONS 15454 and
Cisco ONS 15454 SDH Ethernet Card Software Feature and Configuration Guide, Release 8.0.
CTC provides a graphical representation (map) of IEEE 802.17 RPR circuits between ML-Series cards
with a list of the following information:
•Circuit name
•Type
•Size
•OCHNC Wlen
•Direction
•Protection
•Status
•Source
•Destination
•# of VLANs

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11.11 Section and Path Trace
•# of Spans
•State
•Loopback
Note CTC does not support the display of Cisco proprietary RPR circuit topologies.
Note CTC does not support provisioning or maintenance of IEEE RPR rings. You must use Cisco IOS.
11.11 Section and Path Trace
SDH J1 and J2 path trace are repeated, fixed-length strings composed of 64 consecutive bytes. You can
use the strings to monitor interruptions or changes to circuit traffic. The STM64-XFP and MRC-12 cards
support J0 section trace. Table 11-6 shows the ONS 15454 SDH cards that support J1 path trace. Cards
that are not listed in the table do not support the J1 byte.
Table 11-7 shows cards that support J2 path trace.
If the string received at a circuit drop port does not match the string the port expects to receive, an alarm
is raised. Two path trace modes are available:
•Automatic—The receiving port assumes that the first string it receives is the baseline string.
•Manual—The receiving port uses a string that you manually enter as the baseline string.
Table 11-6 ONS 15454 SDH Cards Capable of J1 Path Trace
J1 Function Cards
Transmit and receive E3-12
DS3i-N-12
G-Series
ML-Series
Receive only OC3 IR 4/STM1 SH 1310
OC12/STM4-4
OC48 IR/STM16 SH AS 1310
OC48 LR/STM16 LH AS 1550
OC192 LR/STM64 LH 1550
Table 11-7 ONS 15454 SDH Cards Capable of J2 Path Trace
J2 Function Cards
Transmit and Receive E1-42
Receive Only STM1E-12

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11.12 Path Signal Label, C2 Byte
11.12 Path Signal Label, C2 Byte
One of the overhead bytes in the SDH frame is the C2 byte. The SDH standard defines the C2 byte as
the path signal label. The purpose of this byte is to communicate the payload type being encapsulated
by the high-order path overhead (HO-POH). The C2 byte functions similarly to EtherType and Logical
Link Control (LLC)/Subnetwork Access Protocol (SNAP) header fields on an Ethernet network; it
allows a single interface to transport multiple payload types simultaneously. Table 11-8 provides the C2
byte hex values.
If a circuit is provisioned using a terminating card, the terminating card provides the C2 byte. A
low-order path circuit is terminated at the cross-connect card and the cross-connect card generates the
C2 byte (0x02) downstream to the VC terminating cards. The cross-connect generates the C2 value
(0x02) to the terminating card. If an STM-N circuit is created with no terminating cards, the test
equipment must supply the path overhead in terminating mode. If the test equipment is in pass-through
mode, the C2 values usually change rapidly between 0x00 and 0xFF. Adding a terminating card to an
STM-N circuit usually fixes a circuit having C2 byte problems.
11.13 Automatic Circuit Routing
If you select automatic routing during circuit creation, CTC routes the circuit by dividing the entire
circuit route into segments based on protection domains. For unprotected segments of circuits
provisioned as fully protected, CTC finds an alternate route to protect the segment, creating a virtual
SNCP. Each segment of a circuit path is a separate protection domain. Each protection domain is
protected in a specific protection scheme including card protection (1+1, 1:1, etc.) or SDH topology
(SNCP, MS-SPRing, etc.).
The following list provides principles and characteristics of automatic circuit routing:
•Circuit routing tries to use the shortest path within the user-specified or network-specified
constraints. Low-order tunnels are preferable for low-order circuits because low-order tunnels are
considered shortcuts when CTC calculates a circuit path in path-protected mesh networks.
Table 11-8 STM Path Signal Label Assignments for Signals
Hex Code Content of the STM Synchronous Payload Envelope (SPE)
0x00 Unequipped
0x01 Equipped—nonspecific payload
0x02 Tributary unit group (TUG) structure
0x03 Locked tributary unit (TU-n)
0x04 Asynchronous mapping of 34,368 kbps or 44,736 kbps into container-3 (C-3)
0x12 Asynchronous mapping of 139,264 kbps into container-4 (C-4)
0x13 Mapping for asynchronous transfer mode (ATM)
0x14 Mapping for Distributed Queue Dual Bus (DQDB)
0x15 Asynchronous mapping for Fiber Distributed Data Interface (FDDI)
0xFE 0.181 Test signal (TSS1 to TSS3) mapping SDH network (see ITU-T G.707)
0xFF Virtual container-alarm indication signal (VC-AIS)

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11.13.1 Bandwidth Allocation and Routing
•If you do not choose Fully Path Protected during circuit creation, circuits can still contain protected
segments. Because circuit routing always selects the shortest path, one or more links and/or
segments can have some protection. CTC does not look at link protection while computing a path
for unprotected circuits.
•Circuit routing does not use links that are down. If you want all links to be considered for routing,
do not create circuits when a link is down.
•Circuit routing computes the shortest path when you add a new drop to an existing circuit. It tries to
find the shortest path from the new drop to any nodes on the existing circuit.
•If the network has a mixture of low-order-capable nodes and low-order-incapable nodes, CTC might
automatically create a low-order tunnel. Otherwise, CTC asks you whether or not a low-order tunnel
is needed.
11.13.1 Bandwidth Allocation and Routing
Within a given network, CTC routes circuits on the shortest possible path between source and destination
based on the circuit attributes, such as protection and type. CTC considers using a link for the circuit
only if the link meets the following requirements:
•The link has sufficient bandwidth to support the circuit.
•The link does not change the protection characteristics of the path.
•The link has the required time slots to enforce the same time slot restrictions for MS-SPRing.
If CTC cannot find a link that meets these requirements, an error appears.
The same logic applies to low-order circuits on low-order tunnels. Circuit routing typically favors
low-order tunnels because low-order tunnels are shortcuts between a given source and destination. If the
low-order tunnel in the route is full (no more bandwidth), CTC asks whether you want to create an
additional low-order tunnel.
11.13.2 Secondary Sources and Destinations
CTC supports secondary sources and destinations (drops). Secondary sources and destinations typically
interconnect two “foreign” networks (Figure 11-6). Traffic is protected while it goes through a network
of ONS 15454 SDH nodes.
Figure 11-6 Secondary Sources and Destinations
83948
Primary source
Secondary source
Primary destination
Secondary destination
Vendor A
network
Vendor B
network
ONS network