Reply: RE: How CRH support SFC/Segment Endpoint option?

["Chengli (Cheng Li)" <[e-mail]>]

Hi Ron,

Thanks for your reply.

I finally get that CRH only support steering packet along a path.

But I am still curious that how to support a specific function/behavior at the specific node by using CRH. Can you please explain that?

Since this is a very basic function we want in the network. SFC needs that, all the services needs that if there is any function/service should be performed at the middle nodes along the path.

We want to provide an integrated service for our customers, because our customers want a integrated solution for providing service, like SFC, VPN, they don’t like us to provide a brick that still need to combine with other many bricks.

IMHO, when comparing solutions, we should compare the same functionality. So could you please provide more info of how CRH supporting services?  It will help people to evaluate the CRH, which can help CRH I think.

Thanks,
Cheng







________________________________

李呈 Cheng Li
Mobile: [phone]<tel:[phone]>
Email: [e-mail]<mailto:[e-mail]>


From: Ron Bonica<[e-mail]<mailto:[e-mail]>>
To: Chengli (Cheng Li)<[e-mail]<mailto:[e-mail]>>;6man<[e-mail]<mailto:[e-mail]>>;spring<[e-mail]<mailto:[e-mail]>>
Cc: spring<[e-mail]<mailto:[e-mail]>>
Subject: RE: How CRH support SFC/Segment Endpoint option?
Time: 2020-05-24 09:24:55

Cheng,

The CRH is a building block. It has exactly one function. That is, to steer a packet along its delivery path.

The CRH does not attempt to deliver parameters or metadata to service function instances. It relies on other mechanisms. One possibility is a destination options header that precedes the CRH. I am sure that there are other mechanisms. CRH should be compatible with all of them.

Personally, I am not an NSH expert. Maybe someone who is can speak up.

                                                                                              Ron




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From: Chengli (Cheng Li) <[e-mail]>
Sent: Saturday, May 23, 2020 12:59 PM
To: Ron Bonica <[e-mail]>; 6man <[e-mail]>; [e-mail]
Cc: [e-mail]
Subject: RE: How CRH support SFC/Segment Endpoint option?

[External Email. Be cautious of content]

Hi Ron,

Thanks for your reply.

Regarding NSH, are you saying to use CRH as a tunnel transport encapsulation between two SFF nodes?
Or we can use a single CRH for steering packet through all the SFF nodes that the NSH packet should visit?

Regarding using the first DOH, how to do that without the container design by your draft[1]?
Or the same option TLV will bind to different behaviors on different nodes according to the node local configuration?

Best,
Cheng


[1]. https://tools.ietf.org/rfcdiff?url2=draft-bonica-6man-seg-end-opt-04.txt<https://urldefense.com/v3/__https:/tools.ietf.org/rfcdiff?url2=draft-bonica-6man-seg-end-opt-04.txt__;!!NEt6yMaO-gk!UD4vf0darQ9cskFhH1fJ9jwZJ-nIciQxgVnf1219YuyyaNcgvNdRUdkjwNmXwyHT$>.


From: Ron Bonica [mailto:[e-mail]]
Sent: Friday, May 22, 2020 10:17 PM
To: Chengli (Cheng Li) <[e-mail]<mailto:[e-mail]>>; 6man <[e-mail]<mailto:[e-mail]>>; [e-mail]<mailto:[e-mail]>
Cc: [e-mail]<mailto:[e-mail]>
Subject: RE: How CRH support SFC/Segment Endpoint option?

Cheng,

The sole purpose of a Routing header is to steer a packet along a specified path to its destination. It shouldn’t attempt to do any more than that.

The CRH does not attempt to deliver service function information to service function instances. However, it is compatible with:


  *   The Network Service Header (NSH)
  *   The Destination Options header that precedes the Routing header

Both of these can be used to deliver service function information to service function instances.

                                                                                                                     Ron




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From: Chengli (Cheng Li) <[e-mail]<mailto:[e-mail]>>
Sent: Friday, May 22, 2020 2:56 AM
To: 6man <[e-mail]<mailto:[e-mail]>>; [e-mail]<mailto:[e-mail]>; Ron Bonica <[e-mail]<mailto:[e-mail]>>
Cc: [e-mail]<mailto:[e-mail]>
Subject: How CRH support SFC/Segment Endpoint option?

[External Email. Be cautious of content]

Hi Ron,

When reading the CRH draft, I have a question about how CRH support SFC?

For example, we have a SID List [S1, S2, S3, S4, S5], and S3 is a SFC related SID, how to indicate that? By PSSI? [1]

But how to know which segment endpoint node/egress node should process this PSSI? At the beginning of the SRm6 design, this is described in [2]. But you deleted the containers [2].

Without that, I don’t really understand how SFC can be supported.


Best,
Cheng



[1]. https://tools.ietf.org/html/draft-bonica-spring-sr-mapped-six-01#section-4.1<https://urldefense.com/v3/__https:/tools.ietf.org/html/draft-bonica-spring-sr-mapped-six-01*section-4.1__;Iw!!NEt6yMaO-gk!UD4vf0darQ9cskFhH1fJ9jwZJ-nIciQxgVnf1219YuyyaNcgvNdRUdkjwP15i-Xa$>
[2]. https://tools.ietf.org/rfcdiff?url2=draft-bonica-6man-seg-end-opt-04.txt<https://urldefense.com/v3/__https:/tools.ietf.org/rfcdiff?url2=draft-bonica-6man-seg-end-opt-04.txt__;!!NEt6yMaO-gk!UD4vf0darQ9cskFhH1fJ9jwZJ-nIciQxgVnf1219YuyyaNcgvNdRUdkjwNmXwyHT$>.