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- Newsgroups: comp.dcom.sys.cisco
- Path: sparky!uunet!boulder!recnews
- From: J.Hayward@utexas.edu (Jeff Hayward)
- Subject: Link level vs routing timeouts
- Message-ID: <9209101644.AA09102@margo.ots.utexas.edu>
- Sender: news@colorado.edu
- Date: 10 Sep 92 11:44:11 CDT
- X-Mailer: ELM [version 2.3 PL11]
- Lines: 26
-
- What do folks do when they want a router to router path to use a LAN
- path as primary, with fallback to a point-point circuit? Here's
- the diagram:
-
- Campus Campus
- ================ =============
- | | |
- +--+ +--+ +--+
- |R1|------------T1-----------------|R2| |R3|
- +--+ +--+ +--+
- | |
- 802.3/4 bridge 802.3/4 bridge
- ==================802.4 MAN===========================
-
- If the MAN loses connectivity between R1 and R3 the routers at each
- site will detect nothing until the routing layer times out (many
- minutes). However, if the T1 were to fail they would detect it within
- seconds via the link-level hellos and initiate a routing change
- accordingly. The cisco link-level check of a LAN only verifies that
- the box can talk to itself, not its peers on the LAN. What can I do
- to get decent fail-over times for this MAN/T1 situation?
-
- Thanks,
- Jeff Hayward
- Office of Telecommunication Services
- The University of Texas System
-