From: gladston@br.ibm.com
Date: Wed Jun 01 2005 - 12:52:28 GMT-3
CAT2 is vtp client.
BB2 is connected to CAT2
If configuring this:
interface FastEthernet0/12
switchport access vlan 300
switchport mode access
no ip address
spanning-tree portfast
Considering the Vlan was not created first, CDP will not be announced.
This was new for me. I though CDP was always advertised, but the following test confirms that if the Vlan does not exist, it is not advertised.
First, CAT2, fa0/12 is configured with and existing Vlan (received from CAT1 via vtp announce).
Then, I change the vlan using 'switchport access vlan 300'. As CAT2 is client, the vlan is not created.
This cause BB2 to loose CDP information.
I can see a problem like this taking our time (during the lab) looking for other configuration problems between CAT2---BB2.
bb2#sh cdp ne
Device ID Local Intrfce Holdtme Capability Platform Port ID
cat2 Eth 0 162 R S I WS-C3550-2Fas 0/12
TERMSERV1>res cat2
[Resuming connection 6 to cat2 ... ]
cat2#sh run int fa 0/12
interface FastEthernet0/12
switchport access vlan 125
switchport mode access
no ip address
spanning-tree portfast
end
cat2#c
cat2(config)#int fa 0/12
cat2(config-if)#sw ac vl 300
cat2#sh vlan
VLAN Name Status Ports
---- -------------------------------- --------- -------------------------------
1 default active Fa0/3, Fa0/4, Fa0/10, Fa0/13
Fa0/14, Fa0/15, Fa0/16, Fa0/17
Fa0/18, Fa0/19, Fa0/20, Fa0/21
Gi0/1, Gi0/2
18 VLAN0018 active Fa0/1
19 VLAN0019 active
26 VLAN0026 active Fa0/6
48 VLAN0048 active
57 VLAN0057 active Fa0/7, Fa0/8
116 VLAN0116 active
125 VLAN0125 active Fa0/5
1002 fddi-default act/unsup
1003 token-ring-default act/unsup
1004 fddinet-default act/unsup
1005 trnet-default act/unsup
TERMSERV1>resu bb2
bb2#sh cdp ne det
-------------------------
Device ID: cat2
Entry address(es):
IP address: 172.16.29.9
Platform: cisco WS-C3550-24, Capabilities: Router Switch IGMP
Interface: Ethernet0, Port ID (outgoing port): FastEthernet0/12
Holdtime : 116 sec
Version :
Cisco Internetwork Operating System Software
IOS (tm) C3550 Software (C3550-I5K2L2Q3-M), Version 12.1(19)EA1c, RELEASE SOFTWARE (fc2
)
Copyright (c) 1986-2004 by cisco Systems, Inc.
Compiled Tue 03-Feb-04 10:39 by yenanh
advertisement version: 2
Protocol Hello: OUI=0x00000C, Protocol ID=0x0112; payload len=27, value=00000000FFFFFF
FF010221FF000000000000000BFDCB1380FF0000
VTP Management Domain: 'ccie'
Native VLAN: 125
Duplex: half
bb2#sh cdp ne det
-------------------------
Device ID: cat2
Entry address(es):
IP address: 172.16.29.9
Platform: cisco WS-C3550-24, Capabilities: Router Switch IGMP
Interface: Ethernet0, Port ID (outgoing port): FastEthernet0/12
Holdtime : 102 sec
Version :
Cisco Internetwork Operating System Software
IOS (tm) C3550 Software (C3550-I5K2L2Q3-M), Version 12.1(19)EA1c, RELEASE SOFTWARE (fc2
)
Copyright (c) 1986-2004 by cisco Systems, Inc.
Compiled Tue 03-Feb-04 10:39 by yenanh
advertisement version: 2
Protocol Hello: OUI=0x00000C, Protocol ID=0x0112; payload len=27, value=00000000FFFFFF
FF010221FF000000000000000BFDCB1380FF0000
VTP Management Domain: 'ccie'
Native VLAN: 125
Duplex: half
bb2#
bb2#clear cdp ta
bb2#sh cdp ne det
bb2#sh cdp ne
Device ID Local Intrfce Holdtme Capability Platform Port ID
bb2#sh cdp ne
Device ID Local Intrfce Holdtme Capability Platform Port ID
bb2#deb cdp pa
CDP packet info debugging is on
bb2#deb cdp ev
CDP events debugging is on
03:37:35: CDP-PA: version 2 packet sent out on Ethernet0
bb2#sh run int e0
Building configuration...
Current configuration : 67 bytes
!
interface Ethernet0
ip address 150.100.2.254 255.255.255.0
end
bb2#
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