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sanity-check-lsp
Enables IS-IS TLV exception checking on this router.
Syntax: [no] sanity-check-lsp
Description: IS-IS TLV exception checking performs a series of semantic and syntax checks on IS-IS packets. Any malformed packets are logged and dropped. The overhead associated with enabling exception checking will negatively affect IGP convergence time due to the delay in installing an LSP and triggering an SPF. The syntax check before flooding will cause some delay in network convergence.
The syntax check determines the syntactic correctness of incoming LSPs for all TLVs by code, length and value.
The following semantic checks are made:
- Presence of NLPID in fragment 0 and that it supports IP.
- Local interface address is checked to assure that it is 32 bits with 0 not allowed in last byte and can not be our address. A check is performed for martian and multicast address.
- For internal reachability the default metric field must be set to internal - bit 7 of default metric set to 0. A check is performed for martian and multicast address.
- For external reachability a check is performed for martian and multicast address.
- The router ID is checked to assure that it is not ours.
- Area address is checked for correctness based on the AFI. For every AFI, the length of the address must have bounds.
- The overload bit must be set in the 0th fragment only. If set, IP external reachability must not be present in subsequent LSPs from that router.
- Host name is checked to assure that an LSP with a different system ID does not have our hostname.
Use the sanity-check-lsp command in IS-IS router configuration mode to enable IS-IS TLV exception checking on this router.
Use the no sanity-check-lsp command in IS-IS router configuration mode to disable IS-IS TLV exception checking.
Factory Default: Disabled.
Command Mode: IS-IS configuration.
Example 1: In the following example IS-IS TLV exception checking is enabled on IS-IS router tsr:
router#configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
router(config)#router isis tsr
router(config-router)#sanity-check-lsp
router(config-router)#end
router#
Example 2: In the following example IS-IS TLV exception checking is disabled on IS-IS router tsr:
router#configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
router(config)#router isis tsr
router(config-router)#no sanity-check-lsp
router(config-router)#end
router#
Related Commands: show isis
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Copyright © 2004
Avici Systems Inc.
Avici® and TSR®
is a registered trademark of Avici Systems Inc.
IPriori™, Composite Links™, SSR™, QSR, and NSR® are
trademarks of Avici Systems Inc.
Source
File Name: ISIS.fm
HTML File Name: ISIS39.html
Last Updated: 05/10/04 at 16:35:45