From: Brian Hescock (bhescock@xxxxxxxxx)
Date: Tue Jun 27 2000 - 16:04:44 GMT-3
Gerard,
Just a quick clarification, are you saying you must turn off ip routing
at the global level, or if you're running IRB / CRB to use "bridge 1 no ip
routing"? The reason I ask is because you can have two interfaces with no
ip addresses at all and bridge between them even if "ip
routing" (global) is turned on. Unless I'm recalling incorrectly, of
course.
R1 with IRB configured ------- E0 [R2] E1 -------- R3 with IRB configured
In the example above R2 doesn't have any ip address on E0 nor E1, only
bridge-group 1. But ip routing (global command) is turned on.
Brian
On Tue, 27 Jun 2000, Gerard Robinson wrote:
>
> IP is always routed unless you issue the command 'no ip routing' or y
ou run CRB so putting an interface into a bridge-group will not bridge IP unles
s you have specifically turned off IP routing by issuing the aforementioned com
mand. If you do a 'sh int irb' you can see which protocols are bridged and whic
h are routed. Once you turn on routing for a protocol and then put a layer 3 ad
dress on an interface then all traffic for that protocol is routed and not brid
ged. So on a interface with an IP address and ip routing enabled all IP traffic
is always routed and non-routable traffic like NetBIOS/SNA is bridged to DLSW
and then encapsulated to IP.
>
> One thing that confuses me is why all example configs for DLSW from a
Token Ring interface are always using source-route bridging, you can use norma
l transparent bridging on Token Ring interface and it works fine so source-rout
e bridging is not a necessity. I think it must be that source-route bridging is
very popular in Token Ring environments and is the bridging of choice for Toke
n Ring.
>
>
> ----- Original Message -----
> From: Earl Aboytes
> To: ccielab@groupstudy.com
> Sent: Monday, June 26, 2000 9:35 AM
> Subject: IRB and DLSW+
>
>
> Here is a question that I thought I had resolved until I started reading th
e doc CD
>
> Assumptions:
>
> When you turn on dlsw in a router you have to bridge from Ethernet to dlsw.
When you turn on dlsw on a router you have to source-route bridge from token
ring to dlsw.
>
> Question:
>
> Did you just ruin routing of IP over the Ethernet and Token if you put it a
bridge group or turn on source route bridging?
>
> Possible answer:
>
> My guess is no. It seems that dlsw turns on IRB automatically. I thought
this was the answer for both token and Ethernet until I read the following pass
age on the Doc CD.
>
>
>
> Integrated routing and bridging is supported for transparent bridging, but
not for source-route bridging (SRB).
>
>
>
> So what is the real answer? Did I lose routing of IP on my token interface
when I turned on SRB? I would guess that dlsw takes care of this. Any though
ts on this?
>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> Earl Aboytes
>
> Senior Technical Conultant
>
> GTE Managed Solutions
>
> 805-381-8817
>
> earl.aboytes@telops.gte.com
>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
>
>
>
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