Subject: I-D ACTION:draft-ash-ospf-isis-congestion-control-02.txt

From: [email-masked]
Date: Wed, 19 Jun 2002 07:27:53 -0400

A New Internet-Draft is available from the on-line Internet-Drafts directories.

	Title		: Proposed Mechanisms for Congestion Control/Failure 
                          Recovery in OSPF & ISIS Networks
	Author(s)	: J. Ash et al.
	Filename	: draft-ash-ospf-isis-congestion-control-02.txt
	Pages		: 
	Date		: 18-Jun-02
	
Earlier papers and contributions identified issues of congestion control and failure recovery for link-state protocol networks, such as OSPF, ISIS, and PNNI networks [maunder, choudhury, pappalardo1, pappalardo2, atm01-0101]. The problem addressed is to enable link-state protocols to a) gracefully recover from massive loss of topology database information, and b) respond gracefully to network overloads and failures. This contribution proposes specific additional considerations for network congestion control/failure recovery.  Candidate mechanisms are proposed for control of network congestion and failure recovery, in particular we initially propose to investigate the following mechanisms:
a)      throttle new connection setups, topology-state updates, and Hello updates based on automatic congestion control mechanisms, 
b)      special marking of critical control messages (e.g., Hello and
topology-state-update Ack) so that they may receive prioritized processing,
c)      database backup, in which a topology database could be automatically recovered from loss based on local backup mechanisms, and 
d)      hitless restart, which allows routes to continue to be used if there is an uninterrupted data path, even if the control path is interrupted due to a failure.
We propose that the OSPF and ISIS working groups include the candidate
mechanisms in an evaluation of congestion control/failure recovery for OSPF and ISIS networks.

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