Re: MPLS Aggregate label

I just read this from one of Roger's Links.....

"
value 0: IPv4 explicit null label
value 1: router alert label
value 2: IPv6 explicit null label
value 3: implicit null label

From above you posted,we know the mpls packet flow in explicit or implicit
null design,we also know why is Explicit. Yes,CoS is available while we use
explicit,but not in implicit,because when implicit,the penultimate LSR
transfers packet to egress LSR with no any label,just a IP packet."

Aaron

On Mar 9, 2011, at 7:11 AM, Aaron <aaron1_at_gvtc.com> wrote:

> I read last night the impl-null is seen on the penultimate lsr ( MPLS router
one hop prior to pe ( edge of MPLS cloud )).... I think impl-null results in
poping of labels(s) .... Check me on this as it's been a while since I learned
about MPLS
>
> Aaron
>
> On Mar 9, 2011, at 5:59 AM, "Roger Pfaeffli" <rpf23543_at_gmail.com> wrote:
>
>> Found another good and quick description in the MPLS Architecture book:
>>
>> Action Description
>> Aggregate Removes the top label in the stack and performs a Layer 3
>> lookup.
>> Pop Removes the top label in the stack and transmits the
>> remaining payload as either a labeled packet or unlabeled IP packet.
>> Push Replaces the top label in the stack with a set of labels.
>> Swap Replaces the top label in the stack with another value.
>> Untag Removes the top label and forwards the IP packet to the
>> specified IP next hop.
>>
>> regards
>>
>> Roger
>>
>> -----Original Message-----
>> From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On Behalf Of
CCIE
>> KID
>> Sent: Mittwoch, 9. Mdrz 2011 12:18
>> To: Cisco certification
>> Subject: MPLS Aggregate label
>>
>> Hey what is the difference between Aggregate label ,implicit null and
>> explicit null label in MPLS
>>
>>
>> --
>> With Warmest Regards,
>>
>> CCIE KID
>> IN PURSUIT OF CCIE
>>
>>
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Received on Wed Mar 09 2011 - 07:19:45 ART