[bess] Re: I-D Action: draft-ietf-bess-rfc7432bis-09.txt

[Luc André Burdet <[e-mail]>]

Hi Wen, Ali,

The addition came from the following discussion:
https://mailarchive.ietf.org/arch/msg/bess/Afnejmi8rOkcrUY55E4YRGD2jkM/

In short, the question was how does one “compare” 4 octets to 16 octets.
> IPv4 read 4 octets as unsigned integer and IPv6 is considered as 16 octet unsigned integer.

The update’s intent is to make explicit the comparison by stating all 4-octet values are “numerically smaller (4<16)” than any 16-octet Originating IP (regardless of known-values, ULA, GUA) before comparing like-to-like dimensions.

Regards,
Luc André

Luc André Burdet |  Cisco  |  [e-mail]  |  Tel: [phone]


From: Wen Lin <wlin=[e-mail]>
Date: Thursday, May 30, 2024 at 23:31
To: Ali Sajassi (sajassi) <[e-mail]>, Ali Sajassi (sajassi) <sajassi=[e-mail]>, [e-mail] <[e-mail]>
Subject: [bess] Re: I-D Action: draft-ietf-bess-rfc7432bis-09.txt
Hi Ali,

Thank you for the investigation.   I think it will be good to specify the followings:

  1.  changing the ordered list from IP address only to a tuple of IP address length and IP address does not change the DF election result.
  2.  the reason for introducing the above change.

Thanks,
Wen




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From: Ali Sajassi (sajassi) <[e-mail]>
Date: Thursday, May 30, 2024 at 11:13 PM
To: Wen Lin <[e-mail]>, Ali Sajassi (sajassi) <sajassi=[e-mail]>, [e-mail] <[e-mail]>
Subject: Re: [bess] Re: I-D Action: draft-ietf-bess-rfc7432bis-09.txt
[External Email. Be cautious of content]

Hi Wen,

Both texts say basically the same thing and translate into the same outcome (7432bis is just a clarification). If you think they don’t, please explain why not or provide an example.  Basically both text say that if you have a mix of IPv4 and IPv6 addresses in a list, sort IPv4 addresses first and then IPv6 addresses (as I said in my previous email). IPv4 values should always be less than IPv6 values for all three types of IPv6 addresses (i.e., ULA, LLA, and GUA).

Cheers,
Ali



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From: Wen Lin <[e-mail]>
Date: Thursday, May 30, 2024 at 11:46 AM
To: Ali Sajassi (sajassi) <sajassi=[e-mail]>, [e-mail] <[e-mail]>, Ali Sajassi (sajassi) <[e-mail]>
Subject: Re: [bess] Re: I-D Action: draft-ietf-bess-rfc7432bis-09.txt

Hi Ali,



Thanks for your explanation.



To illustrate the differences between RFC7432 and RFC7432-bis,  I have included excerpts from both documents below.   To constructing an ordered list under RFC7432, we only extract “Originating Router's IP address" field of the advertised Ethernet Segment route, while under RFC7432-bist, we extract both the "IP Address length" and "Originating Router's IP address" fields of the advertised Ethernet Segment route.   IMHO, some text to explain whether there is any interop issue will be helpful.



RFC7432:

“…each PE builds an ordered list of the IP addresses of all the PE nodes connected to the Ethernet segment (including itself), in increasing numeric value.  Each IP address in this list is extracted from the "Originating Router's IP address" field of the advertised Ethernet Segment route.  Every PE is then given an ordinal indicating its position in the ordered list, starting with 0 as the ordinal for the PE with the numerically lowest IP address. “


RFC7432-bis:
“… each PE builds an ordered list of the IP addresses of all the PE nodes connected to the Ethernet segment (including itself), in increasing numeric value. Each IP address in this list is extracted from the "IP Address length" and "Originating Router's IP address" fields of the advertised Ethernet Segment route. Every PE is then given an ordinal indicating its position in the ordered list, starting with 0 as the ordinal for the PE with the lowest IP address length and numeric value tuple. The tuple list is ordered by the IP address length first and IP address value second. “

Thanks,
Wen




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From: Ali Sajassi (sajassi) <sajassi=[e-mail]>
Date: Thursday, May 30, 2024 at 1:13 PM
To: Wen Lin <[e-mail]>, [e-mail] <[e-mail]>, Ali Sajassi (sajassi) <[e-mail]>
Subject: Re: [bess] Re: I-D Action: draft-ietf-bess-rfc7432bis-09.txt
[External Email. Be cautious of content]

Hi Wen,

The text in RFC7432bis for section 8.5 is basically a clarification to RFC7432 and has been around for several years (i.e., introduced in 2021) to ensure that the order list for DF election is uniformly formed among all the participating PEs in the redundancy group. The intention of RFC7432 was always to allow a mix of IPv4 and v6 in the DF list. So, if the RFC7432 was implemented as intended, then there is no interop or backward compatibility issue (i.e., sort the list based on v4 first and then v6 and further more based on the lowest value first). And if it wasn’t, then we would have an interop issue for those implementation of RFC7432 (i.e., it would be an interop issue and NOT backward compatibility issue!).

Cheers,
Ali



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From: Wen Lin <wlin=[e-mail]>
Date: Thursday, May 30, 2024 at 7:32 AM
To: Ali Sajassi (sajassi) <[e-mail]>, [e-mail] <[e-mail]>, [e-mail] <[e-mail]>
Cc: [e-mail] <[e-mail]>
Subject: Re: [bess] Re: I-D Action: draft-ietf-bess-rfc7432bis-09.txt
Hi Ali,

Under RFC7432,  the ordered list used for electing the DF/BDF is formed based solely on the numerical value of each router’s IP address, the originating router’s IP address.   RFC7432-bis introduces a refinement, i.e., the ordered list is now formed based on the tuple of each router’s IP address length and its numerical value.

It would be helpful to add some text to clarify whether there is any backward combability issue if we have a mixed of IPv4 and IPv6 addresses for the originating router’s IP addresses in the network and with some routers running DF election based on RFC7432 and others based on RFC7432-bis.

Thanks,
Wen




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From: Ali Sajassi (sajassi) <sajassi=[e-mail]>
Date: Wednesday, May 29, 2024 at 11:48 PM
To: Wen Lin <[e-mail]>, [e-mail] <[e-mail]>, [e-mail] <[e-mail]>
Cc: [e-mail] <[e-mail]>
Subject: Re: [bess] Re: I-D Action: draft-ietf-bess-rfc7432bis-09.txt
[External Email. Be cautious of content]

Hi Wen,

There shouldn’t be any backward compatibility issue as section 8.5 states:


    “Every PE is then given an ordinal
       indicating its position in the ordered list, starting with 0 as
       the ordinal for the PE with the lowest IP address length and
       numeric value tuple.  The tuple list is ordered by the IP address
       length first and IP address value second.”

Because IP address length is factored into sorting the list, both IPv4 and IPv6 are allowed to be in the list. This is the expected behavior because in a simple of dual-homing, an ES can span across two ASes with different address families.

Cheers,
Ali





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From: Wen Lin <wlin=[e-mail]>
Date: Wednesday, May 29, 2024 at 12:47 PM
To: Ali Sajassi (sajassi) <[e-mail]>, [e-mail] <[e-mail]>, [e-mail] <[e-mail]>
Cc: [e-mail] <[e-mail]>
Subject: Re: [bess] Re: I-D Action: draft-ietf-bess-rfc7432bis-09.txt
Hi Ali,

Thank you for providing the following text.

I think it will be helpful to mention the backward compatibility issue regarding the change introduced in DF election (Section 8.5) as we need to consider the possibility of originating router’s IP addresses coming in with different IP address families.

Thanks,
Wen





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From: Ali Sajassi (sajassi) <sajassi=[e-mail]>
Date: Wednesday, May 15, 2024 at 1:55 PM
To: Wen Lin <[e-mail]>, [e-mail] <[e-mail]>, [e-mail] <[e-mail]>
Cc: [e-mail] <[e-mail]>
Subject: Re: [bess] Re: I-D Action: draft-ietf-bess-rfc7432bis-09.txt
[External Email. Be cautious of content]

Hi Wen,

I am thinking of adding  the following paragraph as a clarification for the originating router’s IP address.


“The Originating Router’s IP address does not need to be a routable address and its purpose is to identify the originator of that EVPN route uniquely. It can be either IPv4 or IPv6 address independent of the BGP next hop address type for that NLRI and it must remain the same for all EVPN routes advertised by that PE.”



Cheers,

Ali



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From: Wen Lin <wlin=[e-mail]>
Date: Friday, May 10, 2024 at 11:06 AM
To: [e-mail] <[e-mail]>, [e-mail] <[e-mail]>
Cc: [e-mail] <[e-mail]>
Subject: [bess] Re: I-D Action: draft-ietf-bess-rfc7432bis-09.txt
Thank you for the updated draft.

I think we need to explicitly specify how we set the Originating Router’s IP address – when it will be to IPv6 or IPv4 address for both Ethernet Segment Route and Inclusive Multicast Ethernet Tag Route.  Today, there is no mentioning about it in the draft.
7.4. <https://urldefense.com/v3/__https:/datatracker.ietf.org/doc/html/draft-ietf-bess-rfc7432bis-09*section-7.4__;Iw!!NEt6yMaO-gk!D8FxrZ9AXM1VDe0Lr_x1vfnVhlT_Aa-m2k5dfbuYNwjcHjUrl4PwNDjonwQ2by0T_aS2klGdRdmVhPe9_ee4pOSj3vUNqw$> Ethernet Segment Route<https://urldefense.com/v3/__https:/datatracker.ietf.org/doc/html/draft-ietf-bess-rfc7432bis-09*name-ethernet-segment-route__;Iw!!NEt6yMaO-gk!D8FxrZ9AXM1VDe0Lr_x1vfnVhlT_Aa-m2k5dfbuYNwjcHjUrl4PwNDjonwQ2by0T_aS2klGdRdmVhPe9_ee4pOQZKTSEyg$>
            +---------------------------------------+
            |  RD (8 octets)                        |
            +---------------------------------------+
            |Ethernet Segment Identifier (10 octets)|
            +---------------------------------------+
            |  IP Address Length (1 octet)          |
            +---------------------------------------+
            |  Originating Router's IP Address      |
            |          (4 or 16 octets)             |
            +---------------------------------------+

We need to add definition or reference for the Originating Router’s IP Address.
7.3. <https://urldefense.com/v3/__https:/datatracker.ietf.org/doc/html/draft-ietf-bess-rfc7432bis-09*section-7.3__;Iw!!NEt6yMaO-gk!D8FxrZ9AXM1VDe0Lr_x1vfnVhlT_Aa-m2k5dfbuYNwjcHjUrl4PwNDjonwQ2by0T_aS2klGdRdmVhPe9_ee4pORjQTaKBA$> Inclusive Multicast Ethernet Tag Route<https://urldefense.com/v3/__https:/datatracker.ietf.org/doc/html/draft-ietf-bess-rfc7432bis-09*name-inclusive-multicast-etherne__;Iw!!NEt6yMaO-gk!D8FxrZ9AXM1VDe0Lr_x1vfnVhlT_Aa-m2k5dfbuYNwjcHjUrl4PwNDjonwQ2by0T_aS2klGdRdmVhPe9_ee4pOSIekbGxQ$>

            +---------------------------------------+

            |  RD (8 octets)                        |

            +---------------------------------------+

            |  Ethernet Tag ID (4 octets)           |

            +---------------------------------------+

            |  IP Address Length (1 octet)          |

            +---------------------------------------+

            |  Originating Router's IP Address      |

            |          (4 or 16 octets)             |

            +---------------------------------------+



For IMET route, we have the following definition in section 11.1:

“The Originating Router's IP Address field value MUST be set to an IP address of the PE that should be common for all the EVIs on the PE (e.g., this address may be the PE's loopback address). The IP Address Length field is in bits.”



A router may have both IPv4 and IPv6 addresses configured for the loopback.  We need to specify when IPv6 address will be used based on whether EVPN is used IPv4 or IPv6 underlay.
Thanks,
Wen



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From: BESS <[e-mail]> on behalf of [e-mail] <[e-mail]>
Date: Friday, May 3, 2024 at 12:42 AM
To: [e-mail] <[e-mail]>
Cc: [e-mail] <[e-mail]>
Subject: [bess] I-D Action: draft-ietf-bess-rfc7432bis-09.txt
[External Email. Be cautious of content]


Internet-Draft draft-ietf-bess-rfc7432bis-09.txt is now available. It is a
work item of the BGP Enabled ServiceS (BESS) WG of the IETF.

   Title:   BGP MPLS-Based Ethernet VPN
   Authors: Ali Sajassi
            Luc Andre Burdet
            John Drake
            Jorge Rabadan
   Name:    draft-ietf-bess-rfc7432bis-09.txt
   Pages:   73
   Dates:   2024-05-02

Abstract:

   This document describes procedures for Ethernet VPN (EVPN), a BGP
   MPLS-based solution which addresses the requirements specified in the
   corresponding RFC - "Requirements for Ethernet VPN (EVPN)".  This
   document obsoletes RFC7432 (BGP MPLS-Based Ethernet VPN) and updates
   RFC8214 (Virtual Private Wire Service Support in Ethernet VPN).

The IETF datatracker status page for this Internet-Draft is:
https://urldefense.com/v3/__https://datatracker.ietf.org/doc/draft-ietf-bess-rfc7432bis/__;!!NEt6yMaO-gk!DQNdb1zziDhGamgqVCqazNaTWtGRyB4JfRJn_4PBJ-meIo5dUeuj3X1ZZzUL6Ak1xr3TX2QD68p6Le_VrAUK3PyL$<https://urldefense.com/v3/__https:/datatracker.ietf.org/doc/draft-ietf-bess-rfc7432bis/__;!!NEt6yMaO-gk!DQNdb1zziDhGamgqVCqazNaTWtGRyB4JfRJn_4PBJ-meIo5dUeuj3X1ZZzUL6Ak1xr3TX2QD68p6Le_VrAUK3PyL$>

There is also an HTMLized version available at:
https://urldefense.com/v3/__https://datatracker.ietf.org/doc/html/draft-ietf-bess-rfc7432bis-09__;!!NEt6yMaO-gk!DQNdb1zziDhGamgqVCqazNaTWtGRyB4JfRJn_4PBJ-meIo5dUeuj3X1ZZzUL6Ak1xr3TX2QD68p6Le_VrD-_D2Jy$<https://urldefense.com/v3/__https:/datatracker.ietf.org/doc/html/draft-ietf-bess-rfc7432bis-09__;!!NEt6yMaO-gk!DQNdb1zziDhGamgqVCqazNaTWtGRyB4JfRJn_4PBJ-meIo5dUeuj3X1ZZzUL6Ak1xr3TX2QD68p6Le_VrD-_D2Jy$>

A diff from the previous version is available at:
https://urldefense.com/v3/__https://author-tools.ietf.org/iddiff?url2=draft-ietf-bess-rfc7432bis-09__;!!NEt6yMaO-gk!DQNdb1zziDhGamgqVCqazNaTWtGRyB4JfRJn_4PBJ-meIo5dUeuj3X1ZZzUL6Ak1xr3TX2QD68p6Le_VrF5Wvh7P$<https://urldefense.com/v3/__https:/author-tools.ietf.org/iddiff?url2=draft-ietf-bess-rfc7432bis-09__;!!NEt6yMaO-gk!DQNdb1zziDhGamgqVCqazNaTWtGRyB4JfRJn_4PBJ-meIo5dUeuj3X1ZZzUL6Ak1xr3TX2QD68p6Le_VrF5Wvh7P$>

Internet-Drafts are also available by rsync at:
rsync.ietf.org::internet-drafts


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