Extreme Networks ExtremeWare XOS 11.1, Руководство пользователя

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ESRP Concepts
ExtremeWare XOS 11.1 Concepts Guide
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Linking ESRP Switches
When considering system design using ESRP, Extreme Networks recommends using a direct link. Direct
links between ESRP switches are useful under the following conditions:
●
A direct link can provide a more direct routed path, if the ESRP switches are routing and supporting
multiple VLANs where the master/slave configuration is split such that one switch is master for
some VLANs and a second switch is master for other VLANs. The direct link can contain a unique
router-to-router VLAN/subnet, so that the most direct routed path between two VLANs with
different master switches uses a direct link, instead of forwarding traffic through another set of
connected routers.
●
A direct link can be used as a highly reliable method to exchange ESRP hello messages, so that the
possibility of having multiple masters for the same VLAN is lessened if all downstream Layer 2
switches fail.
●
A direct link is necessary for the ESRP host attach (HA) option. The direct link is used to provide
Layer 2 forwarding services through an ESRP slave switch.
Direct links may contain a router-to-router VLAN, along with other VLANs participating in an ESRP
domain. If multiple VLANs are used on the direct links, use 802.1Q tagging. The direct links may be
aggregated into a load-shared group, if desired. If multiple ESRP domains share a host port, each VLAN
must be in a different ESRP group.
ESRP and Hitless Failover—BlackDiamond 10K Switch Only
When you install two Management Switch Fabric Module (MSM) modules in a BlackDiamond chassis,
one MSM assumes the role of primary and the other assumes the role of backup MSM. The primary
MSM executes the switch’s management functions, and the backup MSM acts in a standby role. Hitless
failover transfers switch management control from the primary MSM to the backup MSM and maintains
the state of ESRP. The ESRP extended version supports hitless failover.
For ESRP support of hitless failover, both ESRP switches and the primary and backup MSMs must be
running ExtremeWare XOS 11.0 or later operating in ESRP extended mode.
NOTE
You must run ExtremeWare XOS 11.0 or later for ESRP support of hitless failover.
The ESRP domain on the primary MSM is active and participates in the ESRP protocol. The ESRP
domain on the backup MSM is in the neutral state listening for configuration changes, tracking failures,
and checkpointing messages and link state events. When you initiate MSM failover, the master ESRP
switch notifies its neighbor ESRP switch about the failover. After the neighbor receives information
from the master switch, the neighbor remains in its current state and waits for the failover to occur.
After the failover from the primary MSM to the backup MSM is complete, the master ESRP switch
notifies the neighbor so the neighbor can relinquish its current state.
To initiate hitless MSM failover on a network that uses ESRP:
1 Confirm that the MSMs are synchronized and have identical software and switch configurations
using the
show switch {detail}
command. The output displays the status of the MSMs, with the
primary MSM showing
MASTER
and the backup MSM showing
BACKUP (InSync)
.
If the MSMs are not synchronized, proceed to step 2 .
If the MSMs are synchronized, proceed to step 3 .