Re: [Bier] Comments on draft-ietf-bier-bier-yang

[<[e-mail]>]

Hi Senthil,






Thank you for your quick reply too! :-P


About the ECMP number, it is OK. Let's add a parameter for it because you insist on it. :-)


But seems like it is better to add the parameter in the underlay (OSPF and ISIS) configuration parts for comparing the value with max-ecmp easily.


How do you think about it?






Thanks,


Sandy







原始邮件



发件人：SenthilDhanaraj <[e-mail]>
收件人：张征00007940;
抄送人：Xiejingrong <[e-mail]>;陈然00080434;BIER WG <[e-mail]>;[e-mail] <[e-mail]>;
日 期 ：2019年04月15日 15:11
主 题 ：Re: [Bier] Comments on draft-ietf-bier-bier-yang




Hi Sandy,

Thanks for the quick reply !
Pls check my comments inline !



-
Senthil




On Mon, Apr 15, 2019 at 8:30 AM <[e-mail]> wrote:



Hi Senthil, Jingrong,






Thank you for your review and comments.


I agree with your modification comments about the address-family.


Senthil//  Cool :)




About the encapsulation part:


   |        +--rw encapsulation* [bitstringlength]


   |           +--rw bitstringlength               uint16


   |           +--rw encapsulation-type            enum


   |           +--rw max-si?                       rt-type: uint16


   |           +--rw bift-id-base?                 rt-types: bift-id


Do you think if it's better to use both BSL and encapsulation-type as the keys?


Senthil// Yes. To allow a sub-domain to support many encapsulation-types, both "encapsulation-type" and "bsl" should be key.






About the load-balance-num, IMO it's not necessary to define it in BIER. 


BIER ECMP depends on IGP's ECMP capability. And as Jingrong said, there may be different ECMP path number in different routers.


So at most a ECMP enable capability can be showed in BIER model (sub-domain), it's not necessary to define the specific number.


Senthil//  Multicast routing/forwarding tables and the forwarding procedure itself requires more resources and is expensive compared to unicast forwarding. So i'd prefer allowing the user to configure lesser ECMP number for multicast compared to unicast.


Example, Unciast (ISIS/OSPF) ECMP=64, Multicast(BIER) ECMP=4.
So, even though there are 64 possible unicast ECMP paths, multicast would only use the first 4 ECMP paths.






Thanks,


Sandy







原始邮件



发件人：SenthilDhanaraj <[e-mail]>
收件人：Xiejingrong <[e-mail]>;
抄送人：陈然00080434;[e-mail] <[e-mail]>;[e-mail] <[e-mail]>;
日 期 ：2019年04月15日 13:45
主 题 ：Re: [Bier] Comments on draft-ietf-bier-bier-yang




Dear Yang Authors,
1) I agree to Jingrong's comment that "Same sub-domain cannot be binded to both IPv4 and IPv6 underlay". Pls refer the suggested model to handle this at the end of the mail. Let me know your thoughts/comments.

2) About Jingrong's questions on "Whether same sub-domain can support different encapsulation types like MPLS and Ethernet" ?
I would think - Yes, a single sub-domain can support many encapsulation types. Architecturally it is possible that, for a sub-domain, each hop can chose the encapsulation to be used based on next-hops capability. Yang model should support it. However, we can discuss and clarify this. 

3) A general request to BIER WG is that, we can discuss & progress the yang work at better pace. Traditionally, yang standards progress slowly in IETF resulting in implementation with private yang models :(

Suggested BIER Yang Mode (sd is binded to either ipv4 or ipv6):






   +--rw bier


   |  +--rw bier-global


   |     +--rw default-encapsulation-type?        identityref


   |     +--rw default-bitstringlength?           bsl


   |     +--rw default-bfr-id?                    bfr-id


   |     +--rw default-ipv4-bfr-prefix?           inet:ipv4-prefix


   |     +--rw default-ipv6-bfr-prefix?           inet:ipv6-prefix


   |     +--rw sub-domain* [sub-domain-id] [addr-family]


   |        +--rw sub-domain-id            sub-domain-id


   |        +--rw addr-family            addr-family


   |        +--rw bfr-prefix?  inet:ipv4-ipv6-prefix


   |        +--rw underlay-protocol-type?  underlay-protocol-type


   |        +--rw mt-id?                   mt-id


   |        +--rw bfr-id?                  bfr-id


   |        +--rw bitstringlength?         bsl


   |        +--rw igp-algorithm?           ipa


   |        +--rw bier-algorithm?          Bar


   |        +--rw load-balance-num         uint8


   |        +--rw encapsulation* [bitstringlength]


   |           +--rw bitstringlength               uint16


   |           +--rw encapsulation-type            enum


   |           +--rw max-si?                       rt-type: uint16


   |           +--rw bift-id-base?                 rt-types: bift-id


 
Thanks,Senthil



On Mon, Apr 1, 2019 at 12:10 PM Xiejingrong <[e-mail]> wrote:




Hi Chen Ran,


 


[Ran] "load-balance-number"?Do you means the maximum number of ECMP paths? OSPF YANG data model has defined it .In my opinion, it is neccesarry   to define this item here.


 


[XJR1]:


Yes I found the load-balance(max-ecmp) configuration in OSPF-yang and ISIS-yang, but I think they are different things, and there should be a load-balance-number  for BIER specifically: 


(1)     A BFR may not support BIER ECMP forwarding, while unicast ECMP is supported.  


(2)     There may be different number of paths to different BFERs, for example BFER2/BFER2 may have 3/5 paths separately on a BFR, and this BFR  may want a special load-balance-number 15 for better balancing.


 


[XJR2]:


Second question:


Is it allowed for both IPv4-encapsulation and IPv6-encapsulation being under a single Sub-domain ? 


 


augment /rt:routing:


   +--rw bier


   |  +--rw bier-global


   |     +--rw sub-domain* [sub-domain-id]


   |        +--rw sub-domain-id            sub-domain-id


   |        +--rw underlay-protocol-type?  underlay-protocol-type


   |        +--rw mt-id?                    mt-id


   |        +--rw bfr-id?                   bfr-id


   |        +--rw bitstringlength?          bsl


   |        +--rw igp-algorithm?            ipa


   |        +--rw bier-algorithm?           bar


   |        +--rw af


   |           +--rw ipv4* [bitstringlength bier-mpls-label-base] 


   |           |  +--rw bitstringlength               uint16


   |           |  +--rw bier-mpls-label-base          rt-types:mpls-label


   |           |  +--rw max-si?                       max-si


   |           +--rw ipv6* [bitstringlength bier-mpls-label-base]


   |              +--rw bitstrin+--glength            uint16


   |              +--rw bier-mpls-label-base          rt-types:mpls-label


   |              +--rw max-si?                       max-si


   |


 


The RFC8279 said, a BIER sub-domain must be associated with a single routing underlay (see below). I would understand IPv4 and IPv6 as different  underlay.


   If multiple routing underlays are used in a single BIER domain, each


   BIER sub-domain MUST be associated with a single routing underlay


   (though multiple sub-domains may be associated with the same routing


   underlay).


 


[XJR3]:


Third question, maybe for the BIER WG.


It may also be helpful to discuss and conclude, if it is allowed for both BIER-MPLS encapsulation and BIER-Ethernet encapsulation being under a single  sub-domain?


I feel it unnecessary since one can use different BIER Sub-domains carrying different encapsulations, and thus an MVPN service using BIER doesn’t  have to specify the encapsulation-type. 


 


 


From: [e-mail] [mailto:[e-mail]] 
 Sent: Thursday, September 06, 2018 4:04 PM
 To: Xiejingrong <[e-mail]>
 Cc: [e-mail]; [e-mail]
 Subject: Re: Re: [Bier] Comments on draft-ietf-bier-bier-yang


 

Hi jinrong，

Thanks for your review. Please see inline...

 

Regards.

Ran

 


原始邮件



发件人：Xiejingrong <[e-mail]>



收件人：BIER WG <[e-mail]>



抄送人：[e-mail] <[e-mail]>



日 期 ：2018年07月28日 21:01



主 题 ：Re: [Bier] Comments on draft-ietf-bier-bier-yang




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some more comments:


1.  one sub-domain should allow miltiple {BSL and the according label block}s as encapsulations, see the igp sub-sub-TLV.

[Ran] We will add them ,and  will add the enternet and IPv6 encapsulation type.

2. should the igp-type change to underlay-protocol-type to allow bgp?

[Ran ]will add it.




From:Xiejingrong



To:BIER WG,



Cc:[e-mail],



Date:2018-07-28 20:36:25



Subject:[Bier] Comments on draft-ietf-bier-bier-yang



 



Hi folks,


 


I have the following comments and on draft-ietf-bier-bier-yang.


--should the bier load-balance-number/ipa/bar be added to rt:routing/bier-global/sub-domain (like below)? I think they are some basic items.


 [Ran] "load-balance-number"?Do you means the maximum number of ECMP paths? OSPF YANG data model has defined it .In my opinion, it is neccesarry   to define this item here.


 For the ipa/bar will be added to  rt:routing/bier-global/sub-domain.


augment /rt:routing:


   +--rw bier


   |  +--rw bier-global


   |     +--rw encapsulation-type?   identityref


   |     +--rw bitstringlength?      bsl


   |     +--rw bfr-id?               bfr-id


   |     +--rw ipv4-bfr-prefix?   inet:ipv4-prefix


   |     +--rw ipv6-bfr-prefix?   inet:ipv6-prefix


   |     +--rw sub-domain* [sub-domain-id]


   |        +--rw sub-domain-id      sub-domain-id


   |        +--rw igp-type?          igp-type


   |        +--rw mt-id?             mt-id


   |        +--rw bfr-id?            bfr-id


   |        +--rw bitstringlength?   bsl


   |        +--rw multi-bift-number? load-balance-number


   |        +--rw igp-algorithm?     ipa


   |        +--rw bier-algorithm?    bar


 


--should the bier-mpls-label-range-size be changed to ‘max si’ or not ? The type is uint8 and thus seems having to change the meaning. 


 [Ran] Sure.


 


Thanks


Jingrong


 








 




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