Subject: [OSPF] OSPFv3 Draft 9: Equal-cost paths through mutliple interfaces in a single link

From: "Ramana Koppula-G20085" <[email-masked]>
Date: Thu, 15 Jun 2006 18:57:35 +0800

Hi,
 
In Section 3.9: "The interfaces in this list are used as equal-cost
paths when routes are installed in the routing table."
 
In the same Section: "If the Active Interface fails, another will have
to take over, reforming all neighbor adjacencies from scratch."
 
The motive of equal-cost paths is to retain a route to a router even if
one path goes down.
By mandating the StandBy to reform all the neighbor adjacencies from
scratch, are we not losing that edge.
 
thanx
ramana
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From: Michael J Barnes <[email-masked]>
Date: Thu, 15 Jun 2006 09:58:48 -0700

Hello Ramana,

There are a few reasons for the newly active interface to reform 
adjacencies. First is that it is unknown why the standby interface is no 
longer able to see the hello packets from the active. It is possible, for 
example, that the standby has been physically rewired such that it is 
connected to a different LAN, or a VLAN may have been reconfigured, and 
there are many other possibilities. On top of that, is that the standby 
has a different interface ID and also a different link-local address. It 
must be assured that the neighbors have the correct information. If the 
adjacencies are not reformed, then it is possible that the neighbors will 
keep out of date information in their neighbor data structure and/or LSAs.

Thanks,
Michael

Ramana Koppula-G20085 wrote:
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