Your point about frame map statements and layer 3 addresses brings up and
interesting point. You CAN have a different kind of frame-relay
encapsulation on different PVCs, and you do this with frame relay map
statements.
I don't have time to test it now, but I remember learning that to use frame
relay IP TCP header compression, you have to use the proprietary Cisco frame
relay encapsulation. So if you want to use frame relay IP TCP header
compression or RTP header compression on a PVC, you configure compression
using a frame map statement and that PVC then uses Cisco FR encaps (I think
it is automatically transformed into a cisco FR encaps PVC).
Similarly, if you have frame relay IP TCP header compression on the physical
interface, you can turn off compression on a per-PVC basis using your frame
map statements ("nocompress" comes at the end).
So, you CAN have different encapsulations on a per PVC, sort of. I think
all this business of cisco encapsulation working on a PVC when the
interface is set to ietf (and the frame relay switch is configured for ietf)
works because the FR switch doesn't really care what kind of FR
encapsulation is used on each PVC, while it does care a lot about the
lmi-type. The remote router needs to be set to the correct kind of FR
encapsulation, though (but, again, this can be set per PVC.)
Please feel free to correct me if I am wrong in any particular. I would
hate to have misremembered all or some of this.
Tom Larus, CCIE 10,104
""Srivathsan Ananthachari"" wrote in message
news:[EMAIL PROTECTED]
> If it's possible to assign a network address ( IP / IPX viz., ) to the
> FR sub-interface why not be able to specify encap as well..??
>
> I hope I'm not draggin it.../
>
> Srivathsan
>
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of
> Mwalie W
> Sent: Thursday, June 26, 2003 12:42 PM
> To: [EMAIL PROTECTED]
> Subject: RE: Subinterfaces [7:71421]
>
>
> Hi,
>
> Well, encapsulation is done prior to placing the packets(Frames) to the
> physical medium - I guess it should be done on the physical interface.
>
> I would be interested in what other members have to say, but I think it
> makes sense that it should be on the physical interface.
>
> Mwalie
Message Posted at:
http://www.groupstudy.com/form/read.php?f=7&i=71446&t=71421
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