From: David Hurtado (dei2viccie@hotmail.com)
Date: Mon Jun 14 2004 - 07:46:06 GMT-3
Hello everybody,
It has been a long time since i don't write here (but i still read the
thousands of emails that everybody sends).
I have a problem about IRB in a 3550 switch. I have the following topology:
R1
|
-------------------------
| | |
R5 R6 CAT
All these devices are in the same subnet (192.168.156.X/24) but in different
VLANs (VLAN 20 and 30).
This is the topology of VLAN 20:
R1
|
--------------
| |
R6 CAT
And this is the topology of VLAN 30
R1
|
|
R5
So to communicate between the devices in the different VLANs, i configure
IRB in R1 between VLAN 20 and 30.
Everything works great (everybody can reach everybody) but the Catalyst. The
Catalyst can communicate with all the devices in its VLAN (R1 and R6), but
cannot communicate with the device in the other VLAN (R5).
I have done debugging and i have found that when CAT wants to get the R5's
MAC, it sends an ARP request. This request is received by R5, which answers
advertising its MAC, but the response is never received by CAT.
Here is the debugging on CAT of a ping from CAT to R5
CAT#ping 192.168.156.5
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.156.5, timeout is 2 seconds:
03:23:15: IP ARP: creating incomplete entry for IP address: 192.168.156.5
interf
ace Vlan20
03:23:15: IP ARP: sent req src 192.168.156.10 000c.301f.8580,
dst 192.168.156.5 0000.0000.0000 Vlan20
03:23:16: IP ARP throttled out the ARP Request for 192.168.156.5.
03:23:17: IP ARP: sent req src 192.168.156.10 000c.301f.8580,
dst 192.168.156.5 0000.0000.0000 Vlan20
03:23:18: IP ARP throttled out the ARP Request for 192.168.156.5
03:23:18: IP ARP throttled out the ARP Request for 192.168.156.5
03:23:19: IP ARP: sent req src 192.168.156.10 000c.301f.8580,
dst 192.168.156.5 0000.0000.0000 Vlan20
03:23:20: IP ARP throttled out the ARP Request for 192.168.156.5.
03:23:21: IP ARP: sent req src 192.168.156.10 000c.301f.8580,
dst 192.168.156.5 0000.0000.0000 Vlan20
03:23:21: IP ARP throttled out the ARP Request for 192.168.156.5
03:23:22: IP ARP throttled out the ARP Request for 192.168.156.5.
03:23:23: IP ARP: sent req src 192.168.156.10 000c.301f.8580,
dst 192.168.156.5 0000.0000.0000 Vlan20
03:23:24: IP ARP throttled out the ARP Request for 192.168.156.5
03:23:24: IP ARP throttled out the ARP Request for 192.168.156.5
03:23:25: IP ARP: sent req src 192.168.156.10 000c.301f.8580,
dst 192.168.156.5 0000.0000.0000 Vlan20
03:23:26: IP ARP throttled out the ARP Request for 192.168.156.5.
03:23:27: IP ARP: sent req src 192.168.156.10 000c.301f.8580,
dst 192.168.156.5 0000.0000.0000 Vlan20
03:23:27: IP ARP throttled out the ARP Request for 192.168.156.5
03:23:28: IP ARP throttled out the ARP Request for 192.168.156.5.
Success rate is 0 percent (0/5)
CAT#sh arp
Protocol Address Age (min) Hardware Addr Type Interface
Internet 192.168.156.5 0 Incomplete ARPA
Internet 192.168.156.6 0 0007.5049.c383 ARPA Vlan20
Internet 192.168.156.1 0 0008.21c1.eca0 ARPA Vlan20
Internet 192.168.156.10 - 000c.301f.8580 ARPA Vlan20
Here is the debugging on R5 of a ping from CAT to R5:
R5#
03:21:14: %SYS-5-CONFIG_I: Configured from console by console
03:21:32: IP ARP: rcvd req src 192.168.156.10 000c.301f.8580, dst
192.168.156.5
Ethernet0/0
03:21:32: IP ARP: sent rep src 192.168.156.5 0005.5e1a.9220,
dst 192.168.156.10 000c.301f.8580 Ethernet0/0
03:21:34: IP ARP: rcvd req src 192.168.156.10 000c.301f.8580, dst
192.168.156.5
Ethernet0/0
03:21:34: IP ARP: sent rep src 192.168.156.5 0005.5e1a.9220,
dst 192.168.156.10 000c.301f.8580 Ethernet0/0
03:21:36: IP ARP: rcvd req src 192.168.156.10 000c.301f.8580, dst
192.168.156.5
Ethernet0/0
03:21:36: IP ARP: sent rep src 192.168.156.5 0005.5e1a.9220,
dst 192.168.156.10 000c.301f.8580 Ethernet0/0
03:21:38: IP ARP: rcvd req src 192.168.156.10 000c.301f.8580, dst
192.168.156.5
Ethernet0/0
03:21:38: IP ARP: sent rep src 192.168.156.5 0005.5e1a.9220,
dst 192.168.156.10 000c.301f.8580 Ethernet0/0
03:21:40: IP ARP: rcvd req src 192.168.156.10 000c.301f.8580, dst
192.168.156.5
Ethernet0/0
03:21:40: IP ARP: sent rep src 192.168.156.5 0005.5e1a.9220,
dst 192.168.156.10 000c.301f.8580 Ethernet0/0
03:21:42: IP ARP: rcvd req src 192.168.156.10 000c.301f.8580, dst
192.168.156.5
Ethernet0/0
03:21:42: IP ARP: sent rep src 192.168.156.5 0005.5e1a.9220,
dst 192.168.156.10 000c.301f.8580 Ethernet0/0
03:21:44: IP ARP: rcvd req src 192.168.156.10 000c.301f.8580, dst
192.168.156.5
Ethernet0/0
03:21:44: IP ARP: sent rep src 192.168.156.5 0005.5e1a.9220,
dst 192.168.156.10 000c.301f.8580 Ethernet0/0
03:21:46: IP ARP: rcvd req src 192.168.156.10 000c.301f.8580, dst
192.168.156.5
Ethernet0/0
03:21:46: IP ARP: sent rep src 192.168.156.5 0005.5e1a.9220,
dst 192.168.156.10 000c.301f.8580 Ethernet0/0
R5#sh arp
Protocol Address Age (min) Hardware Addr Type Interface
Internet 192.168.156.5 - 0005.5e1a.9220 ARPA Ethernet0/0
Internet 192.168.156.6 4 0007.5049.c383 ARPA Ethernet0/0
Internet 192.168.156.1 5 0008.21c1.eca0 ARPA Ethernet0/0
Internet 192.168.156.10 1 000c.301f.8580 ARPA Ethernet0/0
Take in account that the switch ports are configured with "switchport mode
access" and "switchport mode trunk". If you want the config files, just ask
me for them.
I hope somebody could tell me why it doesn't work.
Thanks a lot for the help
This archive was generated by hypermail 2.1.4 : Sat Jul 03 2004 - 19:40:40 GMT-3