From: Brian McGahan (bmcgahan@internetworkexpert.com)
Date: Sat Jul 17 2004 - 23:43:00 GMT-3
"I am still not sure how I fixed it but I had some stuff messed up on
the 3550 with my VLAN setup."
That is how you fixed it. Like Ken mentioned, encapsulation
failure means that the router doesn't know what layer 2 address to put
in the packet. If the next hop device was not within your broadcast
domain (i.e. wrong VLAN assignment) it would not have received your
Ethernet ARP packet. Furthermore it would not have been able to reply
with its MAC address, so the router initiating the ping packet wouldn't
know what address to put in the frame, hence encapsulation failure.
HTH,
Brian McGahan, CCIE #8593
bmcgahan@internetworkexpert.com
Internetwork Expert, Inc.
http://www.InternetworkExpert.com
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> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
Of
> trouse@cisco.com
> Sent: Saturday, July 17, 2004 8:34 PM
> To: ccielab@groupstudy.com
> Subject: ENCAP FAILURES ON ETHERNET
>
> I saw something today the blew my mind and time. Guess I always take
> ethernet for granted. But today i was getting encapsulation failure
on
> fastethernet. I had a ip addresss configure but it seems as if the
didnt
> recognize it as connected, however it showed up connected in ip route.
> The "sh int fa 0/0" was up/up. CDP was showing neighbor but I could
not
> pass ip traffic. I am still not sure how I fixed it but I had some
stuff
> messed up on the 3550 with my VLAN setup. And after sorting all this
out.
> Pings worked and encap failure went away. It was doing it on all my
> routers so I want to say it was the switch but....
>
>
> my question is: is there anyway the cat can cause the routers port to
> encap fail. I check the duplex/speed setting and all loooked find on
both
> ends but it was auto negotiated. If this had been my real lab I think
I
> would have cried. Spend over an hour before it finally started
working
> and this was a timed MOCK lab from NM (CheckIt). so I was pretty
> disappointed and upset that my time was wasted. Could this had been a
> bug?
>
> Of couuse the interface was "no shut" since I was getting CDP over it
and
> it saw the connected cat3550 switch.
>
> Thanks
> PUZZLED.....
>
>
This archive was generated by hypermail 2.1.4 : Sun Aug 01 2004 - 10:11:57 GMT-3