H3C S6300 Series User manual

H3C S6300 Switch Series
TRILL Configuration Guide
Hangzhou H3C Technologies Co., Ltd.
http://www.h3c.com
Software version: Release 2418P01
Document version: 6W100-20150717

Copyright © 2015 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
The TRILL Configuration Guide describes the background, fundamentals, and configuration of TRILL.
This preface includes:
•Audience
•Conventions
•About the H3C S6300 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 S6300 series
Conventions
This section describes the conventions used in this documentation set.
Command conventions
Convention Descri
p
tion
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.

Convention Descri
p
tion
&<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 Descri
p
tion
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 Descri
p
tion
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
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.
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.
Represents a security card, such as a firewall, load-balancing, NetStream, SSL VPN, IPS,
or ACG card.
Port numbering in examples
The port numbers in this document are for illustration only and might be unavailable on your device.
About the H3C S6300 documentation set
The H3C S6300 documentation set includes:
Cate
g
or
y
Documents Pur
p
oses
Hardware
specifications and
installation
Compliance and safety manual
CE DOC
Provides regulatory information and the safety
instructions that must be followed during
installation.
Installation quick start Provides basic installation instructions.
Installation guide Provides a complete guide to hardware installation
and hardware specifications.
Fan assemblies installation
manual
Describes the appearance, specifications, and
installation and removal of hot-swappable fan
assemblies.
Power modules user manual
Describes the appearance, specifications, and
installation and removal of hot-swappable power
modules.
Pluggable transceiver modules
installation guide
Guides you through installing SFP/SFP+/QSFP+
transceiver modules.
Pluggable modules manual
Describes the hot-swappable modules available for
the H3C switches, their external views, and
specifications.
Software
configuration
Configuration guides Describe software features and configuration
procedures.
Command references Provide a quick reference to all available
commands.
Operations and
maintenance
MIB Companion Describes the MIBs for the software release.
Release notes
Provide information about the product release,
including the version history, hardware and
software compatibility matrix, version upgrade
information, technical support information, and
software upgrading.


Obtaining documentation
Access the most up-to-date H3C product documentation on the World Wide Web
at http://www.h3c.com.
Click the links on the top navigation bar to obtain different categories of product documentation:
[Technical Support & Documents > 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.
[Technical Support & Documents > Software Download]—Provides the documentation released with the
software version.
Technical support
servic[email protected]
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·······················································································································································3
TRILL forwarding mechanisms ·································································································································3
Protocols and standards ··········································································································································5
Configuration restrictions and guidelines·······················································································································5
TRILL configuration task list···············································································································································6
Enabling TRILL····································································································································································7
Configuration restrictions and guidelines ··············································································································7
Configuration procedure ·········································································································································8
Configuring the system ID and nickname for an RB······································································································8
Configuring the link type of a TRILL port·························································································································8
Configuration procedure ·········································································································································9
Configuring the DRB priority of a TRILL port···················································································································9
Setting the link cost for a TRILL port·································································································································9
Configuring announcing VLANs and the designated VLAN ····················································································· 10
Configuring TRILL timers ················································································································································ 11
Configuring TRILL LSP parameters and features·········································································································· 12
Setting TRILL LSP parameters ································································································································ 12
Enabling TRILL LSP fast advertisement ················································································································· 13
Enabling TRILL pseudonode bypass····················································································································· 14
Setting the SPF algorithm parameters ·························································································································· 14
Configuring TRILL distribution trees ······························································································································ 15
Setting basic distribution tree parameters ·········································································································· 15
Enabling TRILL distribution tree multithread calculation····················································································· 15
Enabling load balancing over TRILL distribution trees ······················································································· 16
Configuring TRILL ECMP routes····································································································································· 16
Enabling incremental flush for TRILL multicast routing entries···················································································· 17
Enabling logging of TRILL neighbor changes·············································································································· 17
Configuring SNMP for TRILL·········································································································································· 18
Enabling TRILL to forward traffic from EVB S-channels······························································································· 18
Configuring TRILL GR ····················································································································································· 19
Associating a TRILL port with a track entry·················································································································· 19
Displaying and maintaining TRILL································································································································· 20
TRILL configuration example·········································································································································· 21
Network requirements··········································································································································· 21
Configuration procedure ······································································································································ 21
Verifying the configuration··································································································································· 24
Index ···········································································································································································26

1
Configuring TRILL
TRansparent Interconnection of Lots of Links (TRILL) uses IS-IS to provide transparent Layer 2 forwarding.
TRILL requires a license. For information about feature licensing, see Fundamentals Configuration Guide.
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 comprised of RBs, as shown in Figure 3.
•System ID—Unique identifier of an RB in the TRILL network. The system ID is 6-byte.
•Nickname—Address of an RB in the TRILL network. The nickname is 2-byte.
•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 protocol frames and data frames.
TRILL protocol frames include TRILL Hello, LSP, CSNP, PSNP, MTU-probe, and MTU-ack. These protocol
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 Descri
p
tion
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.

3
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.
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:
2. A TRILL header (similar to an IP header).
3. An outer Ethernet header (similar to the Ethernet header of a regular Ethernet frame).
4. 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.
5. 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 operations:
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
•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 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 these restrictions and guidelines:
•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.
•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.
Cost=3
Cost = 2
Cost = 1
RB 1
RB 2 RB 3 RB 4

6
For more information about spanning tree protocols, see Layer 2—LAN Switching Configuration
Guide.
•H3C recommends not enabling 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.
•For the TRILL network to forward Layer 3 multidestination traffic correctly, make sure the following
requirements are met:
{The IGMP/MLD snooping version must be the same on all RBs.
{IGMP or MLD must be enabled on the access-facing VLAN interfaces on gateway RBs to prevent
topology changes from interrupting traffic.
•Enabling PIM-DM or IPv6 PIM-DM on core layer and distribution layer devices might cause multicast
traffic duplication. H3C recommends that you use other Layer 3 multicast protocols.
TRILL configuration task list
Tasks at a
g
lance
(Required.) Enabling TRILL
(Required.) 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.) Setting 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.) Enabling TRILL to forward traffic from EVB S-channels
(Optional.) Configuring TRILL GR
(Optional.) Associating a TRILL port with a track entry

7
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
When you enable TRILL, follow these guidelines:
•To enable TRILL on a port, first enable TRILL globally.
•Enable or disable TRILL on all ports in a VLAN, so that the ports in a VLAN have the same TRILL
status (enabled or disabled).
•Do not enable both TRILL and EVB on a port. If the trill evb-support command is not executed on an
EVB-enabled port, make sure the allowed VLANs of the port do not overlap with those of a
TRILL-enabled port. For more information about EVB, see EVB Configuration Guide.
•When you set up a TRILL network, avoid the case that multiple TRILL neighbors are established for
one RB port. When you plan a network, avoid the networks shown in Figure 5 and Figure 6.
{Figure 5 shows a typical network where two TRILL neighbors are established for the same port
of an RB.
{In Figure 6, because TRILL is not enabled on the port connecting RB 2 to RB 3, the port will
transparently transmit the TRILL Hello frames from RB 3. As a result, two TRILL neighbors are
established for the port connecting RB 1 to RB 2.
Figure 5 Two TRILL neighbors are established for a port (1)
Figure 6 Two TRILL neighbors are established for a port (2)
Traditional Ethernet
switch
RB 1
RB 2 RB 3
TRILL enabled port

8
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
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

9
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.
Configuration procedure
To configure the link type 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 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.
Setting the link cost for a TRILL port
The link cost of a TRILL port can be automatically calculated by the system or manually set.
•A manually set link cost takes precedence over a calculated link cost.
•If no link cost is set and automatic link cost calculation is enabled, the calculated link cost takes
effect.
•If no link cost is set and automatic link cost calculation is disabled, the default link cost of 2000 is
used.

10
The system automatically calculates the link cost of a TRILL port by using the following formula: link cost
= 20000000000000/interface baud rate.
To set 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
6. Set 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 an excessive amount of 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

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3. Configure announcing
VLANs. trill announcing-vlan { vlan-list | null }
By default, no announcing VLAN is
configured, and announcing
VLANs are enabled VLANs.
4. Configure the designated
VLAN. trill designated-vlan vlan-id
By default, no designated VLAN is
configured. The system
automatically selects an enabled
VLAN as the designated VLAN.
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.
•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.

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Step Command Remarks
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 TRILL LSP parameters
You can set 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.
•LSP generation timer parameters—By adjusting the TRILL LSP generation timer parameters, you can
prevent frequent network changes from consuming an excessive amount of 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.

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To set TRILL LSP 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.
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:
Ste
p
Command Remarks
1. Enter system view. system-view N/A