Huawei NetEngine80E Configuration Manual - Reliability page 390

HUAWEI NetEngine80E/40E Router
Configuration Guide - Reliability
Table 7-1 Comparison between NSR and NSF
Feature
NSF
Issue 02 (2011-09-10)
Advantage
l Less information needs to be
backed up from the active main
control board to the standby main
control board. Only the following
information needs to be backed up:
– Changes of configuration
information
– Interface status
– Information about neighbors,
protocol status, sending and
receiving of packets, routes, and
topologies
l During the active/standby
switchover of main control boards,
the forwarding plane can still
provide forwarding services.
– During the GR process of a
protocol, topologies and routes
may change, causing
forwarding errors. The occasion
occurs with a very low
probability.
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
7 NSR Configuration
Disadvantage
l Interworking problem: Different
vendors may use different methods
to implement NSF due to immature
standards.
l Depending on neighbor status: A
device needs the help of its neighbor
to complete GR. If all devices
become faulty at the same time due
to a software defect, NSF cannot
work properly.
l Low convergence speed: If an NSF-
enabled device becomes faulty and
is no longer started, the remote
device, however, mistakenly
considers that the NSF device can be
started after a while and does not
delete the routing information
learned from the NSF-enabled
device until the set recovery time
expires. Therefore, routing
information may be incorrect during
this period of time.
373