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Catalyst 4500 Series Switch, Cisco IOS Software Configuration Guide - Cisco IOS XE 3.9.xE and IOS 15.2(5)Ex
Chapter 5 Configuring Virtual Switching Systems
In-Service Software Upgrade (ISSU) on a VSS
on the other switch. If a peer device is connected to the VSS over an MEC that has links terminating in
both switches, that device will not experience a disruption of service during the software upgrade
process. This is illustrated in
.
Figure 5-10 Connecting a Peer Device to VSS to Avoid Service Disruption
Related Documents
Prerequisites to Performing ISSU
Before performing ISSU, you must meet these prerequisites:
•
Ensure that the current Cisco IOS XE version running in the system supports ISSU. Also ensure that
the target version supports ISSU.
•
In a Quad-Supervisor VSS setup, ensure that you copy the Cisco IOS XE image on the standby
supervisors of both the switches, from the VSS Active switch console, using the IOS
copy
command
so that the boot variable has a valid path to point to.
You can enter various commands on the switch to determine supervisor engine versioning and Cisco
IOS XE software compatibility. Alternatively, you can use the ISSU application on Cisco Feature
Navigator to determine this.
•
The type of the pre- and post-upgrade images must match precisely. Identical. ISSU is not supported
from a Universal_lite to a Universal image, or vice versa. ISSU is also not supported from a k9
image to a non-k9 image, or vice versa.
3
44757
V
SS
S
witch #1
V
SS
S
witch #2
Tr
a
ffic on thi
s
link will
b
e
di
s
r
u
pted whenever
S
witch #2
u
ndergoe
s
a
re
b
oot d
u
ring the I
SS
U
proce
ss
.
Tr
a
ffic on thi
s
non-MEC
Etherch
a
nnel will
b
e
di
s
r
u
pted whenever
S
witch #1
u
ndergoe
s
a
re
b
oot d
u
ring the
I
SS
U proce
ss
.
Tr
a
ffic on thi
s
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e di
s
r
u
pted thro
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gho
u
t the I
SS
U proce
ss
.
Whenever one of the V
SS
s
witche
s
u
ndergoe
s
a
re
b
oot, the MEC mem
b
er link goe
s
down,
c
aus
ing the link peer to
s
end
a
ll tr
a
ffic over
the
su
rviving link.
MEC
Related Topic
Document Title
Performing ISSU
Cisco IOS Software: Guide to Performing In Service Software
Upgrades
Summary of Contents for Catalyst 4500 Series
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