20 messages in org.freebsd.freebsd-stableRe: Ethernet MTUs > 1500?| From | Sent On | Attachments |
|---|---|---|
| David Gilbert | Jul 3, 2000 8:22 pm | |
| Joerg Micheel | Jul 3, 2000 8:38 pm | |
| David Gilbert | Jul 3, 2000 8:43 pm | |
| Louis A. Mamakos | Jul 3, 2000 8:52 pm | |
| David Gilbert | Jul 3, 2000 9:37 pm | |
| Louis A. Mamakos | Jul 3, 2000 10:08 pm | |
| Tim Priebe | Jul 4, 2000 3:50 am | |
| Kevin Oberman | Jul 4, 2000 4:24 pm | |
| David Gilbert | Jul 4, 2000 6:46 pm | |
| Tim Priebe | Jul 5, 2000 5:46 am | |
| David Gilbert | Jul 5, 2000 6:20 am | |
| Luigi Rizzo | Jul 5, 2000 8:16 am | |
| Tim Priebe | Jul 5, 2000 9:56 am | |
| Luigi Rizzo | Jul 5, 2000 11:39 pm | |
| Tim Priebe | Jul 6, 2000 5:34 am | |
| David Gilbert | Jul 6, 2000 5:47 am | |
| Tim Priebe | Jul 6, 2000 8:04 am | |
| Luigi Rizzo | Jul 6, 2000 8:28 am | |
| Luigi Rizzo | Jul 6, 2000 8:37 am | |
| Tim Priebe | Jul 6, 2000 9:38 am |
| Subject: | Re: Ethernet MTUs > 1500? | |
|---|---|---|
| From: | Luigi Rizzo (lui...@info.iet.unipi.it) | |
| Date: | Jul 6, 2000 8:28:52 am | |
| List: | org.freebsd.freebsd-stable | |
Naw... that's not how you'd configure it. Lets say we have this:
---------- ---------- ---------- --------- | A |--------| B |--------| C |---------| D | ---------- ---------- ---------- ---------
Now... if a packet leaves A on vlan 57, it will arrive at B marked with vlan 57. If the BC link is the "same" trunk, the packet might continue on vlan 57. Now if the CD link is a different "trunk" (and this is just an organizational issue), then the packet might be rewritten to have vlan 225 on it --- and would make that leg of the journey with vlan 225.
hmm... my understanding was (but i might be wrong) that _normally_ end hosts do not tag packets, the tag insertion/removal (this is what i meant by encapsulation/decapsulation in my previous email) is done by the VLAN bridge when such packets go through a trunk interface (i.e. the link connected to that interface supports traffic for multiple independent VLANs). My point is that you don't know what happens to the traffic on that link -- your network admin could decide to further aggregate such traffic by forwarding it into a "normal" port of another VLAN bridge, which then does the tagging again.
Agreed, this is not how you'd configure it, but as you say
........................ The possibilites simply explode ... not the
In short, vlan tags are not like GRE (which might be the confusion) ... they are simply part of the ethernet header.
not fully sure about that. How could you possibly prevent a frame from being untagged multiple times if the frame has an appropriate bit pattern ?
cheers luigi -----------------------------------+------------------------------------- Luigi RIZZO, lui...@iet.unipi.it . Dip. di Ing. dell'Informazione http://www.iet.unipi.it/~luigi/ . Universita` di Pisa TEL/FAX: +39-050-568.533/522 . via Diotisalvi 2, 56126 PISA (Italy) Mobile +39-347-0373137 -----------------------------------+-------------------------------------
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