H3C S10500 Series User manual

H3C S10500 Switch Series
TRILL
Configuration Guide
Hangzhou H3C Technologies Co., Ltd.
http://www.h3c.com
Software version: S10500-CMW710-R7178
Document version: 6W100-20160118

Copyright © 2016, Hangzhou H3C Technologies Co., Ltd. and its licensors
All rights reserved
No part of this manual may be reproduced or transmitted in any form or by any means without prior written
consent of Hangzhou H3C Technologies Co., Ltd.
Trademarks
H3C, , H3CS, H3CIE, H3CNE,Aolynk, , H3Care, , IRF, NetPilot, Netflow, SecEngine,
SecPath, SecCenter, SecBlade, Comware, ITCMM and HUASAN are trademarks of Hangzhou H3C
Technologies Co., Ltd.
All other trademarks that may be mentioned in this manual are the property of their respective owners
Notice
The information in this document is subject to change without notice. Every effort has been made in the
preparation of this document to ensure accuracy of the contents, but all statements, information, and
recommendations in this document do not constitute the warranty of any kind, express or implied.

Preface
This configuration guide describes TRILL fundamentals and configuration. TRansparent
Interconnection of Lots of Links (TRILL) is suitable for large flat Layer 2 networks in data centers.
This preface includes the following topics about the documentation:
•Audience.
•Conventions.
•About the H3C S10500 documentation set.
•Obtaining documentation.
•Technical support.
•Documentation feedback.
Audience
This documentation is intended for:
•Network planners.
•Field technical support and servicing engineers.
•Network administrators working with the S10500 switch series.
Conventions
This section describes the conventions used in the documentation.
Port numbering in examples
The port numbers in the documentation are for illustration only and might be unavailable on your
device.
Command conventions
Convention Description
Boldface Bold text represents commands and keywords that you enter literally as shown.
Italic Italic text represents arguments that you replace with actual values.
[ ] Square brackets enclose syntax choices (keywords or arguments) that are optional.
{ x | y | ... }
Braces enclose a set of required syntax choices separated by vertical bars, from which
you select one.
[ x | y | ... ]
Square brackets enclose a set of optional syntax choices separated by vertical bars,
from which you select one or none.
{ x | y | ... } *
Asterisk marked braces enclose a set of required syntax choices separated by vertical
bars, from which you select at least one.
[ x | y | ... ] *
Asterisk marked square brackets enclose optional syntax choices separated by vertical
bars, from which you select one choice, multiple choices, or none.
&<1-n> The argument or keyword and argument combination before the ampersand (&) sign
can be entered 1 to n times.
# A line that starts with a pound (#) sign is comments.

GUI conventions
Convention Description
Boldface Window names, button names, field names, and menu items are in Boldface. For
example, the New User window appears; click OK.
> Multi-level menus are separated by angle brackets. For example, File > Create >
Folder.
Symbols
Convention Description
WARNING! An alert that calls attention to important information that if not understood or followed
can result in personal injury.
CAUTION: An alert that calls attention to important information that if not understood or followed
can result in data loss, data corruption, or damage to hardware or software.
IMPORTANT: An alert that calls attention to essential information.
NOTE: An alert that contains additional or supplementary information.
TIP: An alert that provides helpful information.
Network topology icons
Convention Description
Represents a generic network device, such as a router, switch, or firewall.
Represents a routing-capable device, such as a router or Layer 3 switch.
Represents a generic switch, such as a Layer 2 or Layer 3 switch, or a router that
supports Layer 2 forwarding and other Layer 2 features.
Represents an access controller, a unified wired-WLAN module, or the access
controller engine on a unified wired-WLAN switch.
Represents an access point.
Wireless terminator unit.
Wireless terminator.
Represents a mesh access point.
Represents omnidirectional signals.
Represents directional signals.
Represents a security product, such as a firewall, UTM, multiservice security
gateway, or load balancing device.
T
T
T
T





Convention Description
Represents a security card, such as a firewall, load balancing, NetStream, SSL VPN,
IPS, or ACG card.
About the H3C S10500 documentation set
The H3C S10500 documentation set includes the following categories of documents:
Category Documents Purposes
Product description and
specifications Marketing brochures Describes product specifications and benefits.
Hardware specifications
and installation
Compliance and safety
manual
Provides regulatory information and the safety
instructions that must be followed during
installation.
Quick start Guides you through initial installation and setup
procedures to help you quickly set up and use
your device with the minimum configuration.
Installation guide Provides a complete guide to hardware
installation and hardware specifications.
H3C Pluggable SFP
[SFP+][XFP] Transceiver
Modules Installation Guide
Guides you through installing SFP/SFP+/XFP
transceiver modules.
H3C CFP Transceiver
Modules Installation Guide Guides you through installing CFP transceiver modules.
H3C QSFP+ Transceiver
Modules Installation Guide Guides you through installing QSFP+ transceiver modules.
H3C Transceiver Modules
User Guide
Describes the transceiver modules available
for the H3C network products, their external
views, and specifications.
Software configuration
Configuration guides Describes software features and configuration
procedures.
Command references Provides a quick reference to all available
commands.
Configuration examples Describes typical network scenarios and provide configuration examples and
instructions.
Operations and
maintenance
Troubleshooting Provides troubleshooting information for
common problems of using the product.
FAQ Covers the most frequently asked questions about the hardware, software and system
specifications.
Release notes
Provides information about the product
release, including the version history, hardware
and software compatibility matrix, version
upgrade information, technical support
information, and software upgrading.
System log messages Explains the system log messages.

Obtaining documentation
Access the most up-to-date H3C product documentation on the World Wide Web
at http://www.h3c.com.
Click the following links to obtain different categories of product documentation:
[Technical Documents]—Provides hardware installation, software upgrading, and software feature
configuration and maintenance documentation.
[Products & Solutions]—Provides information about products and technologies, as well as
solutions. [Software Download]—Provides the documentation released with the software version.
Technical support
[e-mail]
http://www.h3c.com
Documentation feedback
You can e-mail your comments about product documentation to [e-mail].
We appreciate your comments.

i
Contents
Configuring TRILL··························································································· 1
Overview ····························································································································································1
Basic concepts ···········································································································································1
TRILL frame formats ··································································································································1
How TRILL works·······································································································································2
TRILL forwarding mechanisms ··················································································································3
Protocols and standards ····························································································································5
Configuration restrictions and guidelines ···········································································································5
Licensing requirements ······························································································································5
Hardware requirements······························································································································5
Feature compatibility requirements ············································································································6
TRILL configuration task list·······························································································································7
Enabling TRILL ··················································································································································7
Configuration restrictions and guidelines ···································································································7
Configuration procedure·····························································································································7
Configuring the system ID and nickname for an RB ··························································································8
Configuring the link type of a TRILL port ···········································································································8
Configuring the DRB priority of a TRILL port ·····································································································9
Configuring the link cost for a TRILL port ··········································································································9
Configuring announcing VLANs and the designated VLAN·············································································10
Configuring TRILL timers ·································································································································10
Configuring TRILL LSP parameters and features····························································································11
Setting LSP parameters ···························································································································11
Enabling TRILL LSP fast advertisement ··································································································13
Enabling TRILL pseudonode bypass ·······································································································13
Setting the SPF algorithm parameters·············································································································13
Configuring TRILL distribution trees ················································································································14
Setting basic distribution tree parameters································································································14
Enabling TRILL distribution tree multithread calculation ··········································································15
Enabling load balancing over TRILL distribution trees·············································································15
Configuring TRILL ECMP routes ·····················································································································16
Enabling incremental flush for TRILL multicast routing entries ········································································16
Enabling logging of TRILL neighbor changes ··································································································17
Configuring SNMP for TRILL ···························································································································17
Configuring TRILL GR ·····································································································································18
Associating a TRILL port with a track entry ·····································································································18
Displaying and maintaining TRILL ···················································································································18
TRILL configuration example ···························································································································19
Network requirements ······························································································································19
Configuration procedure···························································································································20
Verifying the configuration························································································································21
Index ··············································································································· 1

1
Configuring TRILL
TRansparent Interconnection of Lots of Links (TRILL) uses IS-IS to provide transparent Layer 2
forwarding.
Overview
TRILL combines the simplicity and flexibility of Layer 2 switching with the stability, scalability, and
rapid convergence capability of Layer 3 routing. All these advantages make TRILL very suitable for
large flat Layer 2 networks in data centers.
Basic concepts
•RBridge—Routing bridge (RB) that runs TRILL. RBs are classified into ingress RBs, transit
RBs, and egress RBs, depending on their positions in the TRILL network. A frame enters the
TRILL network through an ingress RB, travels along transit RBs, and leaves the TRILL network
through an egress RB, as shown in Figure 2.
•TRILL network—A Layer 2 network that contains RBs, as shown in Figure 3.
•System ID—Unique identifier of an RB in the TRILL network. The system ID is 6 bytes in
length.
•Nickname—Address of an RB in the TRILL network. The nickname is 2 bytes in length.
•Link State Database—The LSDB contains all link state information in the TRILL network.
•Link State Protocol Data Unit—An LSP describes local link state information and is
advertised between neighbor devices.
•Designated Routing Bridge (DRB)—Similar to the designated IS (DIS) in IS-IS, a DRB exists
in a broadcast network. It helps simplify network topology, and assigns AVFs and appointed
ports for the VLANs on each RB in the broadcast network.
•Appointed VLAN-x Forwarder (AVF) and appointed port—To avoid loops, TRILL requires all
traffic of a VLAN on a broadcast network to enter and leave the TRILL network through the
same port of an RB. The RB is the VLAN's AVF, and the port is the VLAN's appointed port.
For more information about LSDB, LSPDU, and DIS, see Layer 3—IP Routing Configuration Guide.
TRILL frame formats
TRILL frames include control frames and data frames.
TRILL control frames include TRILL Hello, LSP, CSNP, PSNP, MTU-probe, and MTU-ack. These
control frames use 802.1Q encapsulation and have a fixed destination multicast address
0180-C200-0041.
TRILL data frames have a specific format, as shown in Figure 1. A TRILL header and an outer
Ethernet header are added to the original Ethernet frame.

2
Figure 1 TRILL data frame format
Table 1 describes the fields in the TRILL header.
Table 1 TRILL header fields
Field Description
Ethertype The Ethertype is fixed to TRILL.
V Version number, which is 0. When an RB receives a TRILL frame, it checks the V
field and drops the frame if the Vfield is not 0.
R Reserved for future extension. An ingress RB sets the R field to 0when adding a
TRILL header. Transit RBs and egress RBs ignore the field.
M
Multidestination attribute:
•0—Known unicast frame.
•1—Multidestination frame (multicast, broadcast, or unknown unicast
frame).
Op-Length Length of the Options field. 0indicates that the Options field does not exist.
Hop Count Hop count, which is used to avoid loops. An RB drops a TRILL frame whose hop
count is decremented to 0.
Egress RB Nickname Nickname of the egress RB.
Ingress RB Nickname Nickname of the ingress RB.
Options Options field. This field exists when the Op-Length field is non-zero.
How TRILL works
TRILL establishes and maintains adjacencies between RBs by periodically advertising Hello frames,
distributes LSPs among RB neighbors, and generates an LSDB for all RBs in the network. Based on
the LSDB, each RB uses the SPF algorithm to calculate forwarding entries destined to other RBs.

3
TRILL forwarding mechanisms
Different types of frames are forwarded by using different forwarding mechanisms. The following
sections describe these mechanisms.
Unicast frame forwarding mechanism
As shown in Figure 2, a unicast frame is forwarded as follows:
1. When a unicast frame enters the TRILL network, the ingress RB encapsulates the original
Ethernet frame with the following headers:
{A TRILL header (similar to an IP header).
{An outer Ethernet header (similar to the Ethernet header of a regular Ethernet frame).
2. RBs forward the frame hop by hop according to the egress RB nickname in the TRILL header in
the same way routers forward IP packets. Each hop replaces the outer Ethernet header with an
appropriate outer Ethernet header, and decrements the hop count in the TRILL header.
3. Upon receiving the TRILL frame, the egress RB de-encapsulates it to obtain the original
Ethernet frame, and sends the frame to the target device.
Figure 2 Unicast frame forwarding flow
The outer Ethernet header enables traditional Ethernet switches to forward TRILL frames and
connect RBs.
Multidestination frame forwarding mechanism
In a TRILL network, RBs perform the following tasks:
•Compute a TRILL distribution tree for each VLAN based on the LSDB.
•Guide the forwarding of multidestination frames in each VLAN by using its TRILL distribution
tree.
As shown in Figure 3, when a multicast frame from VLAN 10 enters the TRILL network, RB 1, which
is an ingress RB, encapsulates the multicast frame into a TRILL frame. In the frame, the egress RB is
RB 2, the root bridge of the TRILL distribution tree for VLAN 10. When the frame arrives at the root
VLAN 10 VLAN 200 VLAN 300 VLAN 10
Ingress RB
RB 1
S1 S2
Ethernet frame TRILL frame TRILL frame Ethernet frame
Egress RB
RB 3
Transit RB
RB 2
Ingress RB = RB 1
Outer VLAN = 200
Egress RB = RB 3
Outer S-MAC = RB 1
Outer D-MAC = RB 2
Payload
Inner VLAN = 10
Inner S-MAC = S1
Inner D-MAC = S2
Ingress RB = RB 1
Outer VLAN = 300
Egress RB = RB 3
Outer S-MAC = RB 2
Outer D-MAC = RB 3
Payload
Inner VLAN = 10
Inner S-MAC = S1
Inner D-MAC = S2
Payload
Inner VLAN = 10
Inner S-MAC = S1
Inner D-MAC = S2
Payload
Inner VLAN = 10
Inner S-MAC = S1
Inner D-MAC = S2
Unicast frame

4
bridge, it is distributed throughout the TRILL distribution tree. Then, the TRILL frame is
de-encapsulated by RB 3 and sent to the destination station S2. Because the network segment
where RB 4 resides does not have a receiver of this frame, RB 4 drops the frame.
Figure 3 Multicast frame forwarding flow
TRILL selects distribution trees for forwarding multidestination frames based on the VLANs to which
the frames belong. Because the topologies of TRILL distribution trees are different, traffic can be
load shared. However, equal-cost links are not used for load sharing.
When N equal-cost links exist in the network, each TRILL distribution tree selects the link with the
largest pseudonode ID for forwarding packets. As shown in Figure 4, two equal-cost links exist
between RB 1 and RB 3. Assume the link directly connecting RB 1 to RB 3 has the largest
pseudonode ID. Both the TRILL distribution tree rooted at RB 3 and the TRILL distribution tree rooted
at RB 4 select the link. For more information about pseudonode IDs, see Layer 3—IP Routing
Configuration Guide.
VLAN 10VLAN 10
S1 S2
VLAN 200
TRILL network
RB 1
Ethernet frame
Payload
Inner VLAN = 10
Inner S-MAC = S1
Inner D-MAC = Multi
TRILL frame
Ingress RB = RB 1
Outer VLAN = 200
Egress RB = RB 2
Outer S-MAC = RB 1
Outer D-MAC = All RBs
Payload
Inner VLAN = 10
Inner S-MAC = S1
Inner D-MAC = Multi
TRILL frame
Ingress RB = RB 1
Outer VLAN = 200
Egress RB = RB 2
Outer S-MAC = RB 2
Outer D-MAC = All RBs
Payload
Inner VLAN = 10
Inner S-MAC = S1
Inner D-MAC = Multi
RB 4
RB 3
Ethernet frame
Payload
Inner VLAN = 10
Inner S-MAC = S1
Inner D-MAC = Multi
RB 2
Multicast frame Distribution tree
of VLAN 10
Root bridge of
distribution tree
Leaf of
distribution tree

5
Figure 4 Multicast ECMP
TRILL distribution trees support Equal Cost Multiple Path (ECMP), also known as multicast ECMP.
When multicast ECMP is enabled, TRILL assigns equal-cost links to multiple TRILL distributions
trees. This improves the load sharing performance.
When N equal-cost links exist in the network, each TRILL distribution tree selects an equal-cost link
for forwarding packets through J mod N in root bridge priority order. J is the priority sequence number
of a TRILL distribution tree and starts from 0.
As shown in Figure 4:
•The link directly connecting RB 1 to RB 3 is assigned to the TRILL distribution tree rooted at RB
3.
•The link RB 1-RB 2-RB 3 is assigned to the TRILL distribution tree rooted at RB 4.
TRILL distribution trees support fast root switching. When an RB detects that the root of a distribution
tree is unreachable, the RB deletes the LSP of the root from its LSDB. This triggers recalculation of
all distribution trees in the TRILL network. Multidestination traffic is switched to new distribution trees.
Protocols and standards
•RFC 6325, Routing Bridges (RBridges): Base Protocol Specification
•RFC 6326, Transparent Interconnection of Lots of Links (TRILL) Use of IS-IS
•RFC 6327, Routing Bridges (RBridges): Adjacency
•RFC 1195, Use of OSI IS-IS for Routing in TCP/IP and Dual Environments
Configuration restrictions and guidelines
When you configure TRILL, follow the restrictions and guidelines in this section.
Licensing requirements
TRILL requires a license to run on the device. For information about feature licensing, see
Fundamentals Configuration Guide.
Hardware requirements
TRILL is supported only on the following interface modules:
•SE interface modules:
{LSU1CGC2SE0.
{LSUM2GP24TSSE0.
Cost=3
Cost = 2
Cost = 1
RB 1
RB 2 RB 3 RB 4

6
{LSUM2GP44TSSE0.
{LSUM2GT24PTSSE0.
{LSUM2GT24TSSE0.
{LSUM2GT48SE0.
{LSUM2GV48SE0.
•SF interface modules.
•SG interface modules.
•EC interface modules.
Feature compatibility requirements
When you use TRILL with other features, follow these restrictions and guidelines:
•Do not enable both TRILL and EVB on a port. The allowed VLAN list of a TRILL-enabled port
cannot overlap with that of an EVB-enabled port. For more information about EVB, see EVB
Configuration Guide.
•Do not configure EVI and VXLAN in a TRILL network. For information about EVI, see EVI
Configuration Guide. For information about VXLAN, see VXLAN Configuration Guide.
•Do not assign a TRILL port to a VLAN that is associated with an OpenFlow instance. If the
TRILL port is assigned to the VLAN, traffic might be forwarded incorrectly because forwarding in
the VLAN is based on flow table entries.
•Configuration in Layer 2 Ethernet interface view takes effect only on the current port.
Configuration in Layer 2 aggregate interface view takes effect on the current interface and its
member ports. Configuration on the member port of an aggregate interface takes effect after
the member port leaves the aggregation group. On a Layer 2 aggregate interface, TRILL
distribution tree calculation is done on the aggregate interface rather than its member ports.
•To connect a spanning tree network to a TRILL network, make sure the following requirements
are met:
{The spanning tree protocol is disabled on the TRILL network.
{An edge port is used to connect the spanning tree network to the TRILL network. The edge
port can transit to the forwarding state before DRB election is finished. This prevents
multiple DRBs from being elected.
For more information about spanning tree protocols, see Layer 2—LAN Switching
Configuration Guide.
•As a best practice, do not enable loop detection on TRILL ports, because TRILL avoids loops.
For more information about loopback detection, see Layer 2—LAN Switching Configuration
Guide.
•If IRF is used, retain the IRF bridge MAC address permanently. Otherwise, traffic interruption
might occur after an IRF split. For more information about IRF configuration, see IRF
Configuration Guide.
•Do not configure the TPID for VLAN tags on RBs. For more information about TPIDs, see Layer
2—LAN Switching Configuration Guide.
•To avoid loops, do not connect multiple TRILL ports of an RB to a broadcast network, because
TRILL ports cannot detect each other when they are on a broadcast network. If there are
multiple TRILL ports, they might be elected as the appointed ports of a VLAN at the same time
and result in loops.

7
TRILL configuration task list
Tasks at a glance
(Required.) Enabling TRILL
(Optional.) Configuring the system ID and nickname for an RB
(Optional.) Configuring the link type of a TRILL port
(Optional.) Configuring the DRB priority of a TRILL port
(Optional.) Configuring the link cost for a TRILL port
(Optional.) Configuring announcing VLANs and the designated VLAN
(Optional.) Configuring TRILL timers
(Optional.) Configuring TRILL LSP parameters and features
(Optional.) Setting the SPF algorithm parameters
(Optional.) Configuring TRILL distribution trees
(Optional.) Configuring TRILL ECMP routes
(Optional.) Enabling incremental flush for TRILL multicast routing entries
(Optional.) Enabling logging of TRILL neighbor changes
(Optional.) Configuring SNMP for TRILL
(Optional.) Configuring TRILL GR
(Optional.) Associating a TRILL port with a track entry
Enabling TRILL
After you enable TRILL on a port, TRILL can operate correctly by using default settings. A port with
TRILL enabled is called a TRILL port.
Configuration restrictions and guidelines
To enable TRILL on a port, first enable TRILL globally.
Configuration procedure
To enable TRILL:
Step Command Remarks
1. Enter system view. system-view N/A
2. Enable TRILL globally
and enter TRILL view. trill By default, TRILL is disabled globally.
3. Return to system view. quit N/A
4. Enter Layer 2 Ethernet
or aggregate interface
view.
interface interface-type
interface-number N/A

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Step Command Remarks
5. Enable TRILL on the
port. trill enable By default, TRILL is disabled on a port.
Configuring the system ID and nickname for an
RB
The system ID and nickname of an RB are identifiers of the RB in the TRILL network.
•System ID—Unique identifier of an RB in the TRILL network. The system ID can be
automatically assigned or manually configured.
•Nickname—Address of an RB in the TRILL network. The address can be automatically
assigned or manually configured. When multiple RBs in the TRILL network have the same
nickname, the RB with the highest priority uses the nickname. When the RBs also have the
same priority, the RB with the highest system ID uses the nickname. The system automatically
assigns new nicknames to the other RBs.
The system resets the TRILL process when the RB's system ID changes.
To configure the system ID and nickname for the RB:
Step Command Remarks
1. Enter system view. system-view N/A
2. Enter TRILL view. trill N/A
3. Configure the system
ID for the RB. system-id system-id By default, the RB automatically
generates a system ID based on its MAC
address upon startup.
4. Configure the
nickname for the RB. nickname nickname [ priority
priority ]
By default, TRILL automatically assigns
nicknames to RBs, and the priority for a
RB to hold a nickname is 64.
Configuring the link type of a TRILL port
The following link types are available for a TRILL port:
•Access—Access ports include access ports without the alone attribute and access ports with
the alone attribute. Access ports with the alone attribute do not send or receive Hello frames
and do not participate in DRB election or AVF negotiation. Access ports without the alone
attribute can process only local data frames and Hello frames.
•Hybrid—A hybrid port combines the attributes of an access port and a trunk port, and can
process local data frames and passing data frames.
•Trunk—A trunk port can process passing data frames and some of Layer 2 protocol frames (for
example, LLDP frames), but it cannot process local data frames.
To configure the link type of a TRILL port:
Step Command Remarks
1. Enter system view. system-view N/A

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Step Command Remarks
2. Enter Layer 2
Ethernet or
aggregate interface
view.
interface interface-type
interface-number N/A
3. Configure the link
type of the TRILL
port.
trill link-type { access [ alone ] |
hybrid |trunk } By default, the link type of a TRILL port
is access without the alone attribute.
Configuring the DRB priority of a TRILL port
On a broadcast network, TRILL must elect a DRB. An RB with a higher DRB priority is preferred in
DRB election. When two RBs have the same DRB priority, the RB with a higher MAC address takes
precedence.
To configure the DRB priority of a TRILL port:
Step Command Remarks
1. Enter system view. system-view N/A
2. Enter Layer 2 Ethernet
or aggregate interface
view.
interface interface-type
interface-number N/A
3. Configure the DRB
priority of the TRILL
port. trill drb-priority priority By default, the DRB priority of a TRILL port
is 64.
Configuring the link cost for a TRILL port
The link cost of a TRILL port can be automatically calculated by the system or manually configured.
•A manually configured link cost takes precedence over a calculated link cost.
•If no configured link cost exists and automatic link cost calculation is enabled, the calculated link
cost takes effect.
•If no configured link cost exists and automatic link cost calculation is disabled, the default link
cost of 2000 is used.
The system automatically calculates the link cost of a TRILL port by using the following formula: link
cost = 20000000000000/interface baud rate.
To configure the link cost for a TRILL port:
Step Command Remarks
1. Enter system view. system-view N/A
2. Enter TRILL view. trill N/A
3. Enable automatic link cost
calculation for TRILL ports. auto-cost enable By default, automatic link cost
calculation is enabled for TRILL
ports.
4. Return to system view. quit N/A
5. Enter Layer 2 Ethernet
interface view or Layer 2
aggregate interface view.
interface interface-type
interface-number N/A

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Step Command Remarks
6. Configure the link cost for the
TRILL port. trill cost value The default setting is 2000.
Configuring announcing VLANs and the
designated VLAN
The concepts and symbols used to describe a VLAN on a port are as follows:
•Enabled VLAN—A VLAN enabled on the port.
•Forwarding VLAN—A VLAN for which the port is the appointed port.
•∩and ∪—Set operation symbols. ∩indicates set-theoretic intersection, and ∪indicates
set-theoretic union.
RBs send Hello frames in a set of VLANs. The VLAN set is calculated as follows:
•DRB—Enabled VLANs ∩(announcing VLANs ∪designated VLAN).
•Non-DRB—Enabled VLANs ∩(designated VLAN ∪(announcing VLANs ∩forwarding
VLANs)).
To prevent Hello frames from consuming excessive CPU resources, reduce the number of
announcing VLANs.
RBs use the designated VLAN to forward TRILL protocol frames (except Hello frames) and local data
frames. For RBs to establish adjacencies and forward TRILL data frames, make sure the designated
VLAN is an enabled VLAN.
To configure announcing VLANs and the designated VLAN:
Step Command Remarks
1. Enter system view. system-view N/A
2. Enter Layer 2 Ethernet
interface view or Layer 2
aggregate interface view.
interface interface-type
interface-number N/A
3. Configure announcing
VLANs. trill announcing-vlan { vlan-list |
null }
By default, no announcing VLANs
are configured, and announcing
VLANs are enabled VLANs.
4. Configure the designated
VLAN. trill designated-vlan vlan-id By default, no designated VLAN
is configured.
Configuring TRILL timers
You can configure the following TRILL timers:
•Hello interval and Hello multiplier—The RB advertises Hello frames at the Hello interval to
maintain a TRILL adjacency. The shorter the Hello interval, the faster the network convergence.
However, a shorter Hello interval consumes more system resources. The adjacency holding
time is obtained by multiplying the Hello interval by the Hello multiplier. The RB advertises the
adjacency holding time to neighbors through Hello frames. If a neighbor does not receive any
Hello frame from the RB within the adjacency holding time, it removes the TRILL adjacency with
the RB.

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•AVF inhibition time—As the AVF of a VLAN, the RB guarantees that frames of the VLAN enter
and leave a broadcast network through the same port. Other RBs on the broadcast network do
not process frames from the VLAN.
To avoid loops, the RB suppresses its AVF role during the inhibition time when one of the
following conditions exists:
{The RB detects a root bridge change on the broadcast network.
{Other RBs advertise a different AVF for the VLAN.
When the inhibition time expires, the RB restores its AVF role if it is still the AVF of the VLAN.
•CSNP interval—On a broadcast network, the RB advertises CSNPs at the CSNP interval to
perform network-wide LSDB synchronization if it is elected as the DRB. A CSNP records all LSP
digests of the RB's local LSDB. A remote RB compares a received CSNP against its local LSDB
to verify whether some LSPs are aged out or missing. If the CSNP has an LSP digest that the
local LSDB does not have, the remote RB sends a PSNP packet to request the LSP.
To configure TRILL timers:
Step Command Remarks
1. Enter system view. system-view N/A
2. Enter Layer 2 Ethernet
or aggregate interface
view.
interface interface-type
interface-number N/A
3. Configure the Hello
interval. trill timer hello interval
The default setting is 10 seconds.
This command sets the Hello interval for an
RB. The Hello interval of a DRB is 1/3 of the
Hello interval of an RB. This allows for DRB
failures to be quickly detected.
4. Configure the Hello
multiplier. trill timer holding-multiplier
count The default setting is 3.
5. Configure the AVF
inhibition time. trill timer avf-inhibited time The default setting is 30 seconds.
6. Configure the CSNP
interval. trill timer csnp interval The default setting is 10 seconds.
Configuring TRILL LSP parameters and features
Setting LSP parameters
You can modify the following LSP parameters:
•LSP maximum age—The RB uses the LSP maximum age as the remaining lifetime of the
LSPs that it originates. When the RB detects that the remaining lifetime of an LSP reaches 0
seconds in the LSDB, the RB performs the following tasks:
{Removes the LSP's content.
{Keeps the LSP's digest.
{Sets the LSP's remaining lifetime to 0 and purges the LSP from the network by advertising
the LSP to other RBs.
•LSP refresh interval—A locally originated LSP is forcibly refreshed when its remaining lifetime
is no greater than n: n = LSP maximum age – LSP refresh interval. This mechanism avoids
frequent LSP aging and ensures network stability.

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•LSP generation timer parameters—By adjusting the TRILL LSP generation timer parameters,
you can prevent frequent network changes from consuming excessive bandwidth and device
resources.
When the network is stable, the LSP generation timer is set to the minimum interval for each
LSP generation. When the network is unstable, the LSP generation timer is added by the
incremental interval for each LSP generation until the maximum interval is reached.
•Maximum length of originated LSPs—The RB selects the smallest value from the following
values as the actual maximum length of LSPs to be sent to a neighbor:
{The configured maximum length of originated LSPs.
{The interface MTU.
{The maximum originated LSP length carried in the LSPs sent by the neighbor.
•Maximum length of received LSPs—When the RB receives an LSP that exceeds the length,
the RB drops the LSP.
•Overload bit of LSPs—The RB sets the Overload bit in LSPs if the RB fails and cannot
correctly perform route selection and packet forwarding. When the RB cannot record the
complete LSDB because of insufficient memory, routing calculation errors occur. To make
troubleshooting easier, temporarily exclude the RB from the TRILL network by setting the
Overload bit for the LSPs sent by the RB.
•Minimum LSP interval and maximum number of LSPs transmitted per interval—To avoid
frequent LSP aging in the network, RBs periodically advertise LSPs. The actual refresh interval
of an LSP is determined by both the minimum LSP interval and the maximum number of LSPs
transmitted per interval. To prevent LSPs from being aged out accidentally, set the LSP
maximum age and the LSP refresh interval appropriately.
To adjust LSP-related parameters:
Step Command Remarks
1. Enter system view. system-view N/A
2. Enter TRILL view. trill N/A
3. Set the LSP maximum
age. timer lsp-max-age time The default setting is 1200 seconds.
4. Set the LSP refresh
interval. timer lsp-refresh time The default setting is 900 seconds.
5. Set the TRILL LSP
generation timer
parameters.
timer lsp-generation
maximum-interval
[ minimum-interval
[ incremental-interval ] ]
By default, the maximum LSP generation
interval is 2 seconds, the minimum interval
is 10 milliseconds, and the incremental
interval is 20 milliseconds.
6. Configure the
maximum length of
originated LSPs. lsp-length originate size
The default setting is 1458 bytes.
To prevent the system from generating
error messages, do not set the maximum
length of originated LSPs to be greater
than the maximum length of received
LSPs.
7. Configure the
maximum length of
received LSPs. lsp-length receive size
The default setting is 1492 bytes.
To prevent the system from generating
error messages, do not set the maximum
length of originated LSPs to be greater
than the maximum length of received
LSPs.

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Step Command Remarks
8. Set the Overload bit of
LSPs and set the
lifetime for the set
Overload bit.
set overload [ timeout ]
By default, the Overload bit is not set.
Do not perform this task on the root RB of
a TRILL distribution tree. The root RB
cannot forward traffic when the Overload
bit of LSPs is set on the RB.
9. Return to system view. quit N/A
10. Enter Layer 2 Ethernet
or aggregate interface
view.
interface interface-type
interface-number N/A
11. Configure the
minimum LSP interval
and the maximum
number of LSPs
transmitted per
interval.
trill timer lsp interval [ count
count ]
By default, the minimum LSP interval is 10
milliseconds, and the maximum number of
LSPs transmitted per interval is 5.
Enabling TRILL LSP fast advertisement
LSP fast advertisement enables TRILL to immediately advertise the specified number of LSPs that
invoke SPF calculation. This mechanism improves network convergence time.
To enable TRILL LSP fast advertisement:
Step Command Remarks
1. Enter system view. system-view N/A
2. Enter TRILL view. trill N/A
3. Enable TRILL LSP
fast
advertisement.
flash-flood [ flood-count flooding-count |
max-timer-interval flooding-interval ] *
By default, TRILL LSP fast
advertisement is disabled.
Enabling TRILL pseudonode bypass
This feature disables a DRB from generating LSPs for the pseudonode when the DRB has only one
neighbor on a broadcast network. This reduces the number of LSPs in the network.
To enable the pseudonode bypass feature:
Step Command Remarks
1. Enter system view. system-view N/A
2. Enter Layer 2 Ethernet
interface view or Layer 2
aggregate interface view.
interface interface-type
interface-number N/A
3. Enable the pseudonode
bypass feature. trill bypass-pseudonode enable By default, the pseudonode
bypass feature is disabled.
Setting the SPF algorithm parameters
The RB uses the SPF algorithm to calculate a shortest path tree with itself as the root based on the
LSDB. The RB uses the shortest path tree to determine the next hop to a destination network. By