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Chapter 3
VLANs
The switches use multicast addresses so all neighbor devices receive the
frames. A VTP server creates new VLANs, and that information is propa-
gated through the VTP domain.
Figure 3.5 shows the three different VTP advertisements: client, summary,
and subset.
F I G U R E 3 . 5
VTP advertisement content
The three different types of messages are as follows:
Client requests Clients can send requests for VLAN information to a
server. Servers will respond with both summary and subset advertise-
ments.
Summary These advertisements are sent out every 300 seconds on
VLAN 1 and every time a change occurs.
Subset These advertisements are VLAN specific and contain details
about each VLAN.
Version Code
Rsvd
Mgmt
DLAN
Management domain name
Version code
follows mgmtDLAN
Config revision number
Management domain name
Client Advertisement Request
Summary Advertisement
Start value
Updater identity
MD5 digest
Updater timestamp
Version
Code
Seq-num
Mgmt
DLAN
Managmt domain name
Subset Advertisement
Config revision
VLAN-info field I
VLAN info field N
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