Cisco WS-C2960S-24PD-L Software Guide - Page 106

Discovery through CDP Hops,

Page 106 highlights

Planning a Switch Cluster Chapter 5 Clustering Switches Discovery through CDP Hops By using CDP, a command switch can discover switches up to seven CDP hops away (the default is three hops) from the edge of the cluster. The edge of the cluster is where the last member switches are connected to the cluster and to candidate switches. For example, member switches 9 and 10 in Figure 5-1 are at the edge of the cluster. You can set the number of hops the command switch searches for candidate and member switches by selecting Cluster > Hop Count. When new candidate switches are added to the network, the command switch discovers them and adds them to the list of candidate switches. In Figure 5-1, the command switch has ports assigned to management VLAN 16. The CDP hop count is three. The command switch discovers switches 11, 12, 13, and 14 because they are within three hops from the edge of the cluster. It does not discover switch 15 because it is four hops from the edge of the cluster. Figure 5-1 Discovery through CDP Hops Command switch Management VLAN 16 Member switch 8 Member switch 9 Switch 11 candidate switch Edge of cluster Management VLAN 16 Member switch 10 Switch 12 Switch 13 Candidate switches Switch 14 Switch 15 65281 Catalyst 2900 Series XL and Catalyst 3500 Series XL Software Configuration Guide 5-6 78-6511-08

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5-6
Catalyst 2900 Series XL and Catalyst 3500 Series XL Software Configuration Guide
78-6511-08
Chapter 5
Clustering Switches
Planning a Switch Cluster
Discovery through CDP Hops
By using CDP, a command switch can discover switches up to seven CDP hops away (the default is
three hops) from the edge of the cluster. The edge of the cluster is where the last member switches are
connected to the cluster and to candidate switches. For example, member switches 9 and
10 in
Figure 5-1
are at the edge of the cluster.
You can set the number of hops the command switch searches for candidate and member switches by
selecting
Cluster > Hop Count
. When new candidate switches are added to the network, the command
switch discovers them and adds them to the list of candidate switches.
In
Figure 5-1
, the command switch has ports assigned to management VLAN 16.
The CDP hop count
is three. The command switch discovers switches 11, 12, 13, and 14 because they are within three hops
from the edge of the cluster. It does not discover switch 15 because it is four hops from the edge of the
cluster.
Figure 5-1
Discovery through CDP Hops
Command switch
Member
switch 10
Edge of
cluster
Member
switch 8
Member
switch 9
Switch 11
candidate
switch
Candidate
switches
Management
VLAN 16
Management
VLAN 16
65281
Switch 12
Switch 13
Switch 14
Switch 15