[dhcwg] dhcpv6-24: Interface-ID option
Ralph Droms <rdroms@cisco.com> Thu, 16 May 2002 12:24 UTC
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Date: Thu, 16 May 2002 08:21:10 -0400
From: Ralph Droms <rdroms@cisco.com>
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Subject: [dhcwg] dhcpv6-24: Interface-ID option
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Original comment: > If the relay agent cannot use the address in the link-address field > to identify the interface through which the response to the client > will be forwarded, the relay agent MUST include an Interface-id > option (see section 22.19) in the Relay-forward message. The server I think the interface-id option may be underspecified. If it is included, but there is no valid link-address (which I understand is the reason for defining this particular option), how does the server know which addresses to assign the client? I.e., how does the server know on which link the client is? > The relay agent puts the client's address in the link-address field > regardless of whether the relay agent includes an Interface-id option > in the Relay-forward message. This doesn't seem right to me. I thought that the link-address is supposed to hold the address of the relay agent. Seems wrong to put the client's address in it. The link-address field is what the server uses to figure out which link the client is on (right?). Also, since the client's address is a link-local address, this field doesn't seem to contain useful information for the server in this case. > Servers MAY use the Interface-ID for parameter assignment policies. > The Interface-ID SHOULD be considered an opaque value, with policies > based on exact string match only; that is, the Interface-ID SHOULD > NOT be internally parsed by the server. Shouldn't the first MAY be a MUST? I.e., the link-address field contains no useful information. Also, not sure the above is sufficient. Unless the interface-identifier is somehow stable, it's not clear how the server policy could take it into account. There are no words suggesting the interface-identifier needs to be stable. > interface-id An opaque value of arbitrary length generated > by the relay agent to identify one of the > relay agent's interfaces Any reason not to make this 32 bits? the IPv6 API already has 32-bit interface IDs. Is there any reason to make it larger? Response: Clarified text in 20.1 to emphasize that relay agent fills in link-address field regardless of whether Interface-ID option is used. Added text explaining why interface-identifier for an interface should remain stable. Left interface-id as variable-length value. *** dhcpv6.tty Wed May 15 22:43:36 2002 - --- dhcpv6-24.txt Tue Apr 23 15:35:14 2002 *************** *** 3199,3207 **** will be forwarded, the relay agent MUST include an Interface-id option (see section 22.19) in the Relay-forward message. The server will include the Interface-id option in its Relay-reply message. ! The relay agent fills in the link-address field as described in the ! previous paragraph regardless of whether the relay agent includes an ! Interface-id option in the Relay-forward message. The relay agent copies the source address from the IP datagram in which the message was received from the client into the - --- 3260,3268 ---- will be forwarded, the relay agent MUST include an Interface-id option (see section 22.19) in the Relay-forward message. The server will include the Interface-id option in its Relay-reply message. ! The relay agent puts the client's address in the link-address field ! regardless of whether the relay agent includes an Interface-id option ! in the Relay-forward message. The relay agent copies the source address from the IP datagram in which the message was received from the client into the *************** *** 4548,4558 **** Servers MAY use the Interface-ID for parameter assignment policies. The Interface-ID SHOULD be considered an opaque value, with policies based on exact string match only; that is, the Interface-ID SHOULD ! NOT be internally parsed by the server. The Interface-ID value for ! an interface SHOULD be stable and remain unchanged, for example, ! after the relay agent is restarted; if the Interface-ID changes, a ! server will not be able to use it reliabily in parameter assignment ! policies. 22.20. Reconfigure Message option - --- 4646,4652 ---- Servers MAY use the Interface-ID for parameter assignment policies. The Interface-ID SHOULD be considered an opaque value, with policies based on exact string match only; that is, the Interface-ID SHOULD ! NOT be internally parsed by the server. 22.20. Reconfigure Message option ------- End of forwarded message ------- _______________________________________________ dhcwg mailing list dhcwg@ietf.org https://www1.ietf.org/mailman/listinfo/dhcwg
- [dhcwg] dhcpv6-24: Interface-ID option Thomas Narten
- RE: [dhcwg] dhcpv6-24: Interface-ID option Bernie Volz (EUD)
- Re: [dhcwg] dhcpv6-24: Interface-ID option Ralph Droms
- RE: [dhcwg] dhcpv6-24: Interface-ID option Bound, Jim
- RE: [dhcwg] dhcpv6-24: Interface-ID option Bound, Jim
- RE: [dhcwg] dhcpv6-24: Interface-ID option Bernie Volz (EUD)
- [dhcwg] dhcpv6-24: Interface-ID option Ralph Droms