Re: Last call - RSVP problems

[Yakov Rekhter <yakov@juniper.net>]

Dimitrios,

> The problem with being in meetings is it took me a long
> time to respond -:)
> 
> So, I 'll try to provide a summary of the messages exchanged
> as well as my understanding of our off-line discussion 
> on the applicability of RSVP and LMP Hello mechanisms.
> 
> An attempt on terminology clarification first:
> Control channel: This is a logical channel over which IP 
> control packets are transported between two network elements 
> (for example a UNI-C and UNI-N in the case of the OIF UNI). 
> A control channel can be realized in multiple ways, for example,
> in-fiber using SONET/SDH overhead bytes, out-of-band over an 
> Ethernet, etc. 
> A pair of network elements may be connected by multiple control 
> channels, used either concurrently or in a primary-backup 
> configuration. Control channel failures can be detected using 
> link management procedures, such as the LMP Hello mechanism. 
> 
> Signaling channel: This is a logical channel over which signaling 
> messages are exchanged between two peers. The signaling channel 
> is realized using (potentially multiple) control channels and 
> it operation relies on processing of signaling messages by the 
> respective peer signaling entities. 
> A signaling channel failure is the result of failure of all control 
> channels, or failure of a signaling entity. Signaling channel 
> failures can be detected using the RSVP hello mechanism (assuming
> of course RSVP is the signaling protocol used!).

And then to extend it further we can also talk about routing channel,
which is a logical channel over which routing messages (Hellos,
Link State Updates) are exchanged between two peers. The routing
channel is realized using (potentially multiple) control channels
and its operation relies on processing of routing messages by the
respective peer routing entities.  A routing channel failure is
the result of failure of all control channels, or failure of a
routing entity. Routing channel failures can be detected using the
ISIS/OSPF hello mechanism (assuming ISIS/OSPF is the routing protocol
used).

Yakov.