Re: What is the difference between Punt Adjacency and Glean

Glean helps by not sending an ARP request for each (subsequent)
received packet.
It's the way CEF "remembers" that ARP "is on the way"...

-Carlos

Anthony Sequeira @ 11/03/2011 11:45 -0300 dixit:
> Hi CCIE KID!
>
> The punt adjacency of the Cisco Express Forwarding adjacency table occurs
> when CEF does not possess the required information to switch the packet. CEF
> uses this entry to trigger subsequent requests to use a "next best"
> switching method such as Fast Switching in order to forward the packet. This
> is easy for fans of American football to remember, as when a team no longer
> believes they can move the ball forward, they PUNT and deliver the ball to
> another team. I am proud to say my New England Patriots rarely ever punt
> (except against the New York Jets in the playoffs).
>
> A glean adjacency is what occurs when the device does not have ARP cache
> address information for the destination. It will create the glean adjacency
> in the table, and then go about the ARP process. This helps to avoid
> ARP-based Denial of Service attacks for the local device. I remember this
> one because I think of the device out on the network trying to "glean" the
> information. According to Merriam-Webster, to glean is to "to gather
> information or material bit by bit".
>
> Note that these subtleties of Cisco Express Forwarding should be of most
> concern during the CCIE written, as opposed to the CCIE lab exam.
>
> I hope this post helps you!
>
> Anthony Sequeira, CCIE, CCSI
> StormWind's Epic Live
>
> -----Original Message-----
> From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On Behalf Of CCIE
> KID
> Sent: Friday, March 11, 2011 6:16 AM
> To: Cisco certification
> Subject: What is the difference between Punt Adjacency and Glean Adjancency
>
> Can anyone tell me the difference between punt and glean adjacency?
>

-- 
Carlos G Mendioroz  <tron_at_huapi.ba.ar>  LW7 EQI  Argentina
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