Huawei NetEngine80E Configuration Manual - Reliability page 462

HUAWEI NetEngine80E/40E Router
Configuration Guide - Reliability
Comparison Between the GR and the HSB
Table 6-1 Comparison between the GR and the HSB
Name
GR
Issue 02 (2014-09-30)
Thus, the GR Restarter completes the AMB/SMB switchover during which packet
forwarding is not interrupted.
Advantage
l It is easy to implement and does not
need great modifications to the
existing software.
l It does not need to back up the
protocol status information.
l Few data needs to be backed up
from the AMB to the SMB. The
data includes configuration
modification, updated messages
and events, interface status change,
and topology information and
routing information from
neighbors after restart.
l During the switchover, there is
little probability of service
interruption.
l Normally, the network converges
rapidly.
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6 GR Configuration
Drawback
l Interoperability: Some of the GR
specifications are still drafts and the
implementation varies with
vendors.
l Concurrent collapse: If a GR router
and its neighbor(s) collapse
concurrently, GR cannot work
normally.
l Long convergence time: When a GR
router in the Down state cannot
recover again, its neighbors assume
that the GR Restarter will restart, so
the neighbors do not delete the
related routing and topology
information before the Recovery
timer times out. Compared with the
common network in which the
routers do not have the GR
capability, this network takes a
longer period to converge.
l Dependence of the recovery process
on neighbor routers: Neighboring
routers must support the GR
capability, because GR is not "self-
contained".
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