03-16-2003 05:41 AM - edited 03-02-2019 05:54 AM
Hi all,
I tested the fallback bridge in 3550 but not work.the following is the diagram:
3550--------R1
.........|____R2
In 3550, f0/1 is connected to R1, f0/2 is connected to R2.
I set the ip of the R1 to 192.192.192.192/24, the ip of R2 to 192.192.192.193/24. I also added the command to 3550:
bridge 1 protocol vlan-bridge
int f0/1
no switchport
no ip address
bridge-group 1
no shut
int f0/2
no switchport
no ip address
bridge-group 1
no shut
But I can not ping R2 from R1 and also in R1 I can not ping R2. use "debug ip packet" command in R1 , there is an encapsulation fail. In 3550 I use "show bridge 1" command and see the f0/1 and f0/2 is in "forward" status. But I think R1 can reach R2 because fallback bridge can bridge the frames that the switch can not route and the non-routed frame.Where did I do wrong? Can anybody tell me? Thank You!
Best Regards
Teru Lei
03-20-2003 11:43 PM
am having the same problem. It seems that the way fallback bridging works is different from bridge-group function in router. I was searching the 3550 config guide and found this line in Configuring network security section: (
http://www.cisco.com/en/US/customer/products/hw/switches/ps646/products_configuration_guide_chapter09186a00800c9fe8.html )(search for keyword "non-arp").
"Only non-IP, non-ARP packets can be fallback-bridged."
So I guess that because arp packets can not be fallback-bridged, when you do a ping, arp packets are not forwarded to other bridge ports and you will get an encapsulation fail error.
03-21-2003 01:31 AM
Hi,
Thank You for your reply. So I also think fallback-bridge use different technique. Did you try to use "arp" command to specify the mac and ip mapping to test? Thank You!
Best Regards
Teru Lei
03-26-2003 07:16 AM
You may want to recheck your routing configuration. You can successfully bridge non-ip (I've not work with fallback bridging) but not be successfull with routing. Are you performing dynamic routing or static? You should configure another router port (no switchport) or a L3 VLAN utilizing another unique subnet on each 3550 in addition to your current subnet configuration and test IP routing once again. Make sure to configure static routes on each 3550 or utilize dynamic routing. In fact, it might be wise to test IP routing with various subnets first prior to testing fallback bridging. Good luck!
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