Reference Guide

Example of Verifying Line Card Configuration After Clearing Mismatch Status
%RPM0-P:CP %CHMGR-5-CARDDETECTED: Line card 0 present
%RPM0-P:CP %CHMGR-3-CARD_MISMATCH: Mismatch: line card 0 is type E48VB - type
E48TB required
FTOS#show linecard all
-- Line cards --
Slot Status NxtBoot ReqTyp CurTyp Version Ports
---------------------------------------------------------------------------
0 type mismatch online E48TB E48VB 7-5-1-71 48
[output omitted]
FTOS(conf)#linecard 0 E48VB
Aug 6 14:25:22: %RPM0-P:CP %IFMGR-1-DEL_PORT: Removed port: Gi 0/0-47
FTOS(conf)#Aug 6 14:25:24: %RPM0-P:CP %CHMGR-5-LINECARDUP: Line card 0 is up
FTOS#show linecard all
-- Line cards --
Slot Status NxtBoot ReqTyp CurTyp Version Ports
---------------------------------------------------------------------------
0 online online E48VB E48VB 7-5-1-71 48
[output omitted]
Hitless Behavior
Hitless behavior is supported only on the S4820T platform. Hitless behavior is supported on S4820T with FTOS version
8.3.19.0 and later.
Hitless is a protocol-based system behavior that makes an RPM failover on the local system transparent to remote
systems. The system synchronizes protocol information on the standby and primary RPMs such that, in the event of an
RPM failover, it is not necessary to notify the remote systems of a local state change.
Hitless behavior is defined in the context of an RPM failover only and does not include line card, SFM, and power
module failures.
• On the S4820T platform: Only failovers via the CLI are hitless. The system is not hitless in any other scenario.
Hitless protocols are compatible with other hitless and graceful restart protocols. For example, if hitless open shortest
path first (OSPF) is configured over hitless the link aggregation control protocol (LACP) link aggregation groups (LAGs),
both features work seamlessly to deliver a hitless OSPF-LACP result. However, to achieve a hitless end result, if the
hitless behavior involves multiple protocols, all protocols must be hitless. For example, if OSPF is hitless but bidirectional
forwarding detection (BFD) is not, OSPF operates hitlessly and BFD flaps upon an RPM failover.
The following protocols are hitless:
• Link aggregation control protocol. Refer to Configuring LACP as Hitless.
• Spanning tree protocol. Refer to Configuring Spanning Trees as Hitless.
Graceful Restart
Graceful restart is supported on the S4820T platform.
Graceful restart (also known as non-stop forwarding) is a protocol-based mechanism that preserves the forwarding
table of the restarting router and its neighbors for a specified period to minimize the loss of packets. A graceful-restart
router does not immediately assume that a neighbor is permanently down and so does not trigger a topology change. On
the S4820T platform, packet loss is non-zero, but trivial, and so is still called hitless.
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