From: Toh Soon, Lim (tohsoon28@gmail.com)
Date: Sun Sep 02 2007 - 06:18:57 ART
Hi Group,
This is my first time configuring bridging and I'm facing an issue which I
lack the fundamental knowledge to troubleshoot. Hope you can help me out.
Router R8 has a 802.1Q trunk to a Cat3550 (Cat1) passing VLANs 8 & 81. IRB
is enabled. Router BB2 is connected to Cat1 on VLAN81. Cat1 has an SVI in
VLAN8. All these 3 devices are on the same IP subnet 172.16.8.0/24 ->
R8(.1), BB2(.102) & Cat1(.11).
Cat1 Config
-----------
!
spanning-tree vlan 1-4094 priority 24576
!
interface FastEthernet0/8
description *** Trunk to R8 ***
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 8,81
switchport mode trunk
switchport nonegotiate
spanning-tree portfast trunk
!
interface FastEthernet0/12
description *** To BB2 ***
switchport access vlan 81
switchport mode access
spanning-tree portfast
!
interface Vlan8
ip address 172.16.8.11 255.255.255.0
!
R8 Config
---------
!
bridge irb
!
interface FastEthernet0/0
description ** Trunk to Cat1 ***
no ip address
!
interface FastEthernet0/0.8
encapsulation dot1Q 8
bridge-group 1
!
interface FastEthernet0/0.81
encapsulation dot1Q 81
bridge-group 1
!
interface BVI1
ip address 172.16.8.1 255.255.255.0
!
bridge 1 protocol ieee
bridge 1 route ip
!
BB2 Config
----------
!
interface FastEthernet0/0
ip address 172.16.8.102 255.255.255.0
!
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
R8 can ping to both BB2 and Cat1. But BB2 and Cat1 can't ping to each other.
They seem to successfully ARP each other, as follows:
Cat1#sh ip arp vl 8
Protocol Address Age (min) Hardware Addr Type Interface
Internet 172.16.8.1 1 0012.01f6.0c00 ARPA Vlan8
Internet 172.16.8.11 - 000c.3076.7300 ARPA Vlan8
Internet 172.16.8.102 0 001b.54ce.1f84 ARPA Vlan8
R8#sh ip ar bvi 1
Protocol Address Age (min) Hardware Addr Type Interface
Internet 172.16.8.1 - 0012.01f6.0c00 ARPA BVI1
Internet 172.16.8.11 1 000c.3076.7300 ARPA BVI1
Internet 172.16.8.102 0 001b.54ce.1f84 ARPA BVI1
BB2#sh ip arp
Protocol Address Age (min) Hardware Addr Type Interface
Internet 172.16.8.1 2 0012.01f6.0c00 ARPA FastEthernet0/0
Internet 172.16.8.11 2 000c.3076.7300 ARPA FastEthernet0/0
Internet 172.16.8.102 - 001b.54ce.1f84 ARPA FastEthernet0/0
Cat1#sh span su
Switch is in pvst mode
Root bridge for: VLAN0001, VLAN0004, VLAN0006-VLAN0012, VLAN0040, VLAN0046
VLAN0051, VLAN0056, VLAN0076, VLAN0089, VLAN0100, VLAN0111, VLAN0127
VLAN0200, VLAN0300, VLAN0567
Cat1#sh span root
Root Hello Max Fwd
Vlan Root ID Cost Time Age Dly Root Port
---------------- -------------------- --------- ----- --- --- ------------
VLAN0008 24584 000c.3076.7300 0 2 20
15
VLAN0081 24584 000c.3076.7300 38 2 20 15
Fa0/8
Is this normal behavior or I'm missing something in my config? If I connect
an external router to Cat1 on VLAN8, it has no problem pinging to BB2 and
R8.
Thank you.
B.Rgds,
Lim TS
This archive was generated by hypermail 2.1.4 : Sat Oct 06 2007 - 12:01:09 ART