Subject: Consensus action: ACCEPT [LL17] Hosts with configured addresses MUST ARP for v4 LL addresses

From: Erik Guttman <[email-masked]>
Date: Mon, 17 Feb 2003 17:58:00 +0100

ACTION:	Accept

RESULT:	Make the following change in section 2.6

    If the destination address is in the 169.254/16 prefix (including
    the 169.254.255.255 broadcast address), the host SHOULD use its
    link-local source address, if it has one. If the host does not have
    a link-local source address, then it MUST ARP for the destination
    address and then send its packet, with a routable source IP address
    and a link-local destination IP address, directly to the destination
    on the same physical link. In many network stacks, achieving this
    functionality may be as simple as adding a routing table entry
    indicating that 169.254/16 is directly reachable on the local link.

becomes:

    If the destination address is in the 169.254/16 prefix (including
    the 169.254.255.255 broadcast address), then it MUST be routed
    directly to the destination address and then send its packet
    directly to the destination on the same physical link.  In many
    network stacks, achieving this functionality may be as simple as
    adding a routing table entry indicating that 169.254/16 is
    directly reachable on the local link.

Add to the terminology section:

    directly routed

       A datagram is directly routed to a destination if it is sent
       to the destination address.  A datagram that is directly
       routed MUST NOT be sent to another address so that it will
       be forwarded to the destination address.

---

From: Keith Moore <[email-masked]>
Date: Tue, 18 Feb 2003 11:47:29 -0500

1. the definition proposed for "directly routed" could stand lots of 
   improvement.  the first sentence is meaningless (or at least, the
   meaning is opaque) and the second sentence tries to define "directly
   routed" in terms of how not to do it.  MUST NOT probably doesn't
   belong in a definition anyway.

   suggest:

   A datagram is directly routed to a destination if the sending host
   treats the destination address as if the destination host were attached
   to a local link.  For Ethernet-like link-layers this means that an
   ARP request is sent over an appropriate network interface, a link-layer 
   destination address is obtained from the ARP reply, and the datagram
   is sent to that link-layer destination.  A datagram is not directly
   routed if it is sent to another address (e.g. that of a router) so that
   it will be forwarded to the destination host.

2. if you're going to define a term "directly routed" then I suggest that
   the text that uses the term spell it the same way, rather than "routed
   directly".

Keith

On Mon, 17 Feb 2003 17:58:00 +0100