Hi Pushpasis,
Thanks a lot for replying.
The requirement is still under research stage once it is in a
presentable format will share the details.
we need every node on the path to perform the same service, we could even
define a service globally and allocate one label to it which is understandable
by all.
Technically it must be possible right, as top label specifies
to service once that service is performed then refer ILM/NHLFE table for
forwarding and if service label says before sending out the packet push the
label back on the stack.
The Egress device will finally pop both service and node label.
Hope you are refering to with respect to SFC
https://tools.ietf.org/html/draft-xu-spring-sfc-use-case-02”
As per below section a node label and service lable combination
has to be pushed for each hop if the service is intended to be performed by
each node on the path to destination.
If there is any metadata involved for service NSH has to be
piggybacked in the packet. SFC don’t solve in reducing number of labels
involved.
The service classifier therefore would attach a
segment list {SID(SN1), SID(SF1), SID(SN2), SID(SF2)} to the packet.
This segment list is actually represented by a MPLS label stack. In
addition, the service classifier could optionally impose metadata on
the packet through the Network Service Header (NSH)
Thanks & Regards
Anil S N
“Be liberal in what you accept, and conservative in what you send” - Jon Postel
From: Pushpasis Sarkar [mailto:[email protected]]
Sent: 10 September 2015 00:45
To: Gaurav agrawal; Alexander Vainshtein
Cc: Anil Kumar S N (VRP Network BL); [email protected]; [email protected]; Vinod
Kumar S 70786
Subject: Re: [spring] [SPRING] Query related to SR Architecture
Hi Gaurav,
Looks like you are asking the routers to forward looking at the second
innermost label and not the topmost label. This does NOT fit into the MPLS
architecture. I am not sure it fits SR-IPV6 architecture or not, but I doubt.
Looks like your requirement is that each node on shortest path to the final
destination (indicated by the bottom-most Node-segment) provide some service.
In this regard, can you be specific about wether all the nodes will provide the
same service or different service? It does not make sense to me for all the
transit nodes to execute the same service on the packet. So if they are not
required to provide the same service on each transit node, question is how one
service label will be enough to indicate which specific service will need to be
executed at each node.
Hope you have gone through SFC drafts already.
Thanks
-Pushpasis
From: spring on behalf of Gaurav agrawal
Date: Wednesday, September 9, 2015 at 6:09 PM
To: Alexander Vainshtein
Cc: "Anil Kumar S N (VRP Network BL)",
"[email protected]<mailto:[email protected]>",
"[email protected]<mailto:[email protected]>", Vinod Kumar S 70786
Subject: Re: [spring] [SPRING] Query related to SR Architecture
Dear Alexander,
Thanks for your inputs. Let me further elaborate on the subject.
The requirement is to make every node on the path to destination to perform a
specific service(Service could be anything).
Currently Service label can only follow a Node Label, because of which to let
every node perform same service, SR Label stack expects to have node and
service label for each transit node, this results in huge label stack.
If we can push a service label prior to node label & each intermediate node can
perform below operation:
1) Pop Service Label & perform/schedule the service.
2) Decide the further forwarding based on Node Label
3) Push the service label back to stack.
With this we needn’t repeat the service label for each transit node thereby
making the SR Label stack COMPACT.
We can derive many optimized implementation by having this.
So, we would like to hear from You and MPLS/SPRING community about our view
point.
Thanks and Regards,
Gaurav Agrawal
[Company_logo]
Mobile: +91-7838700296
Email: [email protected]<mailto:[email protected]>
Huawei Technologies Co., Ltd.
From: Alexander Vainshtein [mailto:[email protected]]
Sent: Wednesday, September 09, 2015 5:01 PM
To: Gaurav agrawal
Cc: Anil Kumar S N (VRP Network BL); Vinod Kumar S 70786;
[email protected]<mailto:[email protected]>; [email protected]<mailto:[email protected]>
Subject: RE: [SPRING] Query related to SR Architecture
Gaurav,
Not sure I understand the context for your requirement.
But to the best of my understanding your requirement does not match MPLS
architecture.
Regards,
Sasha
Office: +972-39266302
Cell: +972-549266302
Email:
[email protected]<mailto:[email protected]>
From: spring [mailto:[email protected]] On Behalf Of Gaurav agrawal
Sent: Wednesday, September 09, 2015 1:38 PM
To: [email protected]<mailto:[email protected]>
Cc: Anil Kumar S N (VRP Network BL); Vinod Kumar S 70786
Subject: [spring] [SPRING] Query related to SR Architecture
Hi,
We would like to have a label stack with only two labels such a way that
service label is a top label and the bottom label would be SR destination node
label. This is to make sure each intermediate node perform the specified
service based on the top label while reaching the destination.
We would appreciate if anyone could clarify whether SR architecture could allow
a service label to be a top label in a label stack.
Thanks and Regards,
Gaurav Agrawal
[Company_logo]
Mobile: +91-7838700296
Email: [email protected]<mailto:[email protected]>
Huawei Technologies Co., Ltd.
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