Dear Mohamed,

Thank you for your insightful suggestions. 

We have carefully considered your comments and uploaded version 14, please find 
our inline replies below for details. 

Please let us know if you have any further comments.

B.R.

Ruibo

 

 

发件人: [email protected] [mailto:[email protected]] 
发送时间: 2026年2月3日 19:13
收件人: Weiqiang Cheng
抄送: aretana.ietf; buraglio; draft-ietf-spring-dhc-distribute-srv6-locator-dhcp; 
spring-chairs; spring; The IESG
主题: RE: [spring] Mohamed Boucadair's Discuss on 
draft-ietf-spring-dhc-distribute-srv6-locator-dhcp-13: (with DISCUSS and 
COMMENT)

 

Hi Weiqiang, 

 

Thank you for the follow-up. 

 

Apologies for the delay to replay as I was out last week. 

 

Please see inline.

 

Cheers,

Med

 

De : Weiqiang Cheng <[email protected]> 
Envoyé : jeudi 22 janvier 2026 12:48
À : BOUCADAIR Mohamed INNOV/NET <[email protected]>; The IESG 
<[email protected]>
Cc : aretana.ietf <[email protected]>; buraglio 
<[email protected]>; 
draft-ietf-spring-dhc-distribute-srv6-locator-dhcp 
<[email protected]>; spring-chairs 
<[email protected]>; spring <[email protected]>
Objet : Re: [spring] Mohamed Boucadair's Discuss on 
draft-ietf-spring-dhc-distribute-srv6-locator-dhcp-13: (with DISCUSS and 
COMMENT)

 

Dear Mohamed,

Thank you very much for your thorough review and insightful comments on our 
draft. 

We have carefully considered all of your comments and please see our inline 
replies below for details. 

Please let us know if you have any further thoughts or comments.

B.R.

Weiqiang

 

 

From: Mohamed Boucadair via Datatracker <mailto:[email protected]> 

Date: 2026-01-16 23:46

To: The IESG <mailto:[email protected]> 

CC: aretana.ietf <mailto:[email protected]> ; buraglio 
<mailto:[email protected]> ; 
draft-ietf-spring-dhc-distribute-srv6-locator-dhcp 
<mailto:[email protected]> ; 
spring-chairs <mailto:[email protected]> ; spring <mailto:[email protected]> 

Subject: [spring] Mohamed Boucadair's Discuss on 
draft-ietf-spring-dhc-distribute-srv6-locator-dhcp-13: (with DISCUSS and 
COMMENT)

Mohamed Boucadair has entered the following ballot position for

draft-ietf-spring-dhc-distribute-srv6-locator-dhcp-13: Discuss

 

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email addresses included in the To and CC lines. (Feel free to cut this

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The document, along with other ballot positions, can be found here:

https://datatracker.ietf.org/doc/draft-ietf-spring-dhc-distribute-srv6-locator-dhcp/

 

 

 

----------------------------------------------------------------------

DISCUSS:

----------------------------------------------------------------------

 

Hi Weiqiang, Ruibo, Changwang, Daniel, and Geng,

 

Thank you for the effort put into this specification.

 

Thanks to Ran Chen for the OPSDIR review. I would appreciate a reply from the

authors.

 

Please find below some DISCUSSion points:

 

# Deployment Assumptions, Pre-requisites: Clarity

 

Other than the need to make it clear this is a sample topology, and not

questioning which CPE class will support SR and that many statements here do

not apply for Enterprise CEs, Section 3 has several issues that are

problematic. Specifically:

 

## Administrative domains boundaries

 

CURRENT:

   This

   deployment assumes that all of the relevant components in Figure 1

   are part of a single trusted SR domain.

 

It is not clear where the CPE is located (is it within the customer premises or

is it within the provider network).

 

There are several deployments out there for the location of CE/CPE. Note that

there might be cases where a managed CE can even be used to service multiple

customers (see rfc9889#section-3.3).

 

If this is within the customer premises, how is this considered as “single

trusted SR domain” given the attachment circuit between the Customer and

Provider is co-managed and do not technically belong to a single domain?

 

[Co-authors] The term 'Trusted Domain' has been discussed many times without a 
final clear definition. Based on previous discussions, at least one consensus 
is that all devices within the same operator's administrative domain are 
considered to be in the 'trusted domain,' where all devices and ports can be 
monitored and managed by the network management system. 

Even if the CPE is located within the customer premises, as long as the device 
itself and its ports are under the operator's administration, the risks remain 
manageable. However, it is indeed necessary to highlight potential risks. The 
co-author will add a risk statement regarding 'the attachment circuit between 
the Customer and Provider' in the new version.

[Med] OK. Please add some text to call out these assumptions. You may consider 
delimiting the administration perimeters (customer, provider) in your figure as 
well. 

[Co-authors][v2]thanks, we updated it in chapter 3 of version 14.

 

## If the managed CPE is within the network provider, then what operational

issues are solved by mimicking DHCP-PD for SR here?

 

[Co-authors]  There are two issues we hope to address: 

First, the number of customer-side devices may be substantial, making manual 
configuration inefficient.  

[Med] This one can be achieved with automation.

[Co-authors] [v2] Yes, the basic resources like IPv4/IPv6 address/locators 
needs to be allocated firstly, then the customer-side devices could be 
connected remotely, then other configurations could be achieved with 
automation. 

 

Second, on the BRAS side, SRv6 Locator routes cannot be dynamically distributed 
to WAN.

[Med] Do you mean at the routing level?

  [Co-authors] [v2] Yes.

 

## Are Locators the only needed provisioning task to CPEs to have intra-access

SR service?

 

[Co-authors] While SRv6 Locator configuration is a key element, a complete 
provisioning solution encompasses more. It should be noted that this document 
focuses specifically on the configuration of SRv6 Locators; other aspects of 
provisioning are outside its current scope.

[Med] Noted. My comment was whether we have an operational solution if only the 
DHCP extension is in place? There is a dependency that I think we need to 
clarify in this spec. 

  [Co-authors] [v2]Yes, if only the DHCP extension is in place for locators,  
an operational solution is to add other configurations via CLI, NETCONF/YANG, 
APIs, etc. We added some descriptions in chapter 3 of version 14.

 

CURRENT:

   In this network, operators hope to achieve interconnection between

   access users through End-to-End SRv6 tunnels.  Taking the service

   traffic from Host1 to Host2 as an example, CPE1 is the SRv6 ingress

   node and CPE2 is the SRv6 egress node.

 

Unless I’m missing something, extra configuration is needed so that SR source

nodes (CPE in this case) can place “End-to-End SRv6 tunnels”. If my

understanding is correct, then there will be a need of a mix set of mechanisms

to provision the CPE. Is it justified from an operational standpoint to have

several mechanisms here instead of using a common provisioning mechanism?

 

[Co-authors]  As mentioned above, additional configuration is indeed required. 
However, considering that customer-side devices are often low-cost boxes that 
may not even support IGP, using DHCP is an economical and straightforward 
approach.  

[Med] I still see a tension here between the part where we say that “additional 
configuration is indeed required” and argument here. A way to close this is to 
have some text that says that there are deployment cases where having a mix of 
solutions to supply portions of required SR configuration may (or may not) be 
operationally viable. Such assessment is out of scope of this document.

 [Co-authors] [v2] Thanks, we updated it in chapter 3 of version 14 about 
adding configurations via CLI, NETCONF/YANG, APIs, etc.

 

## Mobility Requirements

 

CURRENT:

      Moreover, the mobility requirements

      of CPEs are relatively high, and the access location of the same

      CPE often changes, so its IPv6 address cannot be fixed.

 

I fail to understand this.

 

I don’t see from where we have this “high” requirement for CPE mobility. At

least, I don’t see how we can claim that as a general assumption, “access

location” of CPEs “often changes”.

 

## BTW, I don’t see how the use of DHCP solves this issues, especially given

the discussion in RFC7225 about “Additional States Considered Harmful”.

 

[Co-authors] The frequent changes in the access location of the same CPE is 
indeed not the primary issue to be addressed in this document. As suggested, we 
will revise the relevant descriptions.

[Med] Thanks.

 

 

## Some of these issues can be fixed by having less words in Section 3.

 

[Co-authors] We will optimize the text of section 3. 

[Med] ACK

 

# Multiple instances and RFC7227 Guidance

 

CURRENT:

   A client can explicitly request multiple SRv6 Locator prefixes by

   sending multiple IA_SRV6_LOCATOR options.

 

and

 

   A DHCP message may contain multiple IA_SRV6_LOCATOR

   Options (though each must have a unique IAID).

 

and

 

   After receiving a DHCP message with multiple IA_SRV6_LOCATOR options

   at the same time, whether the server can assign multiple SRv6

   Locators to the client depends on the server policy, which is out of

   scope for this document.

 

This seems to conflict with this RFC 7227 guidance:

 

  “If multiple instances are allowed, the document MUST explain how to use

  them.”

 

[Co-authors] This document does not change the original DHCPv6 mechanism, 
please refer to the description in  
<https://datatracker.ietf.org/doc/html/draft-ietf-dhc-rfc8415bis-12#name-multiple-addresses-and-pref>
 
https://datatracker.ietf.org/doc/html/draft-ietf-dhc-rfc8415bis-12#name-multiple-addresses-and-pref.

[Med] Thanks, but my comment is about the new option defined in this spec.

  [Co-authors] [v2] Thanks, we updated it in chapter 4 and chapter 5 of version 
14 based on the ietf-dhc-rfc8415bis(now it is RFC9915.

 

## BTW, other guidance from RFC 7227 seems not followed here such as: template

for the defining the option (rfc7227#section-21), etc. Please check that

guidance, if not done. Thanks

 

[Co-authors] We will update the text to ensure it is fully aligned with the 
guidance from RFC 7227.

[Med] Thanks

 

# "Automatic" behaviors are problematic

 

CURRENT:

   Upon receiving the Release message, the server MUST remove the lease

   and free the locator, making it available for allocation to other

   clients.

 

This MUST is problematic as it assumes that the message will always be valid

and that there is no policy to discard the release.

 

There are other similar constructs in the document that I think need to be

fixed.

[Co-authors]  We will revise all similar statements as suggested.

[Med] ACK.

 

----------------------------------------------------------------------

COMMENT:

----------------------------------------------------------------------

 

# General: please update all DHCP occurrences to DHCPv6.

[Co-authors] Got it. 

[Med] Thanks.

 

# You may cite RFC 7084 for considerations related to PD support.

[Co-authors] Will update. 

[Med] ACK

 

# Several of the considerations in RFC 8987 can be leveraged here are well

[Co-authors] Will update.  

[Med] Thanks.

 

Specifically, I would mirror the following Operational ones from RFC 8987

(replace delegated prefix with locator):

 [Co-authors] Will update. 

[Med] Thanks

   O-1:  The relay SHOULD implement an interface allowing the operator

         to view the active delegated prefixes.  This SHOULD provide

         information about the delegated lease and client details such

         as the client identifier, next-hop address, connected

         interface, and remaining lifetimes.

 

   O-2:  The relay SHOULD provide a method for the operator to clear

         active bindings for an individual lease, client, or all

         bindings on a port.

 

   O-3:  To facilitate troubleshooting of operational problems between

         the delegating relay and other elements, it is RECOMMENDED that

         a time synchronization protocol be used by the delegating

         relays and DHCP servers.

 

# Routing stability as an additional Operational Considerations

 

In some setups, an aggregate is announced instead of individual prefixes for

the sake of optimized RIBs. Withdrawal of specific routes triggered by releases

may have lead to shrink announcements. An alternative behavior is to have a

policy that governs that behavior. In such cases, the delegating routers will

drop packets sent to specific prefix not “delegated” on the customer-facing

interface.

 

# Nits

 

## What is the purpose of the following?

 

CURRENT:

   Telecom providers can use their IP Metro and Backbone networks to

   establish connectivity between access users who are located in

   different regions.

 

Isn’t obvious that a network provider uses its network to provided intra-domain

connectivity?

[Co-authors] Got it. We will update.  

[Med] ACK/

 

## Paradigm and “any program”

 

CURRENT:

   The network programming paradigm for SRv6 is specified in [RFC8986].

   It describes how any behavior can be bound to a SID and how any

   network program can be expressed as a combination of SIDs.  It also

   describes several well-known behaviors that can be bound to SRv6

   SIDs.

 

I suggest to simply state what that spec is about

 

NEW:

   [RFC8986] introduces the SRv6 Network Programming concept

   and specifies the base set of SRv6 behaviors.

 [Co-authors] Got it.  

[Med] ACK.

 

Cheers,

Med

 

 

 

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