Cisco Catalyst 4500 Series, Software Configuration Manual

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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 45 Configuring AVC with DNS-AS
About AVC with DNS-AS
Figure 45-1 AVC with DNS-AS Process Flow
High Availability and ISSU for AVC with DNS-AS
The AVC with DNS-AS feature supports High Availability and ISSU.
For High Availability, the binding table database of the active DNS-AS client is synchronized with the
standby DNS-AS client. As long as AVC with DNS-AS is enabled, no additional user configuration is
required.
The binding table entries are synchronized when:
• The standby comes up (bulk synchronization).
•
New entries are added to the binding table database.
•
One or more entries are cleared from the database.
Note AVC with DNS-AS is also supported in the VSS mode, and Quad-Supervisor VSS Mode.
1 Host 3 Authoritative DNS Server
2 DNS-AS Client
An “A” record request from
the host to the DNS server An “A” record response from the
DNS server to the host
A copy of the host’s “A”
record request that the
DNS-AS client saves — —
TXT record and “A” record
request from the DNS-AS
client to the DNS server TXT record and “A” record
response from the DNS server to
the DNS-AS client
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