Subject: [ipoverib] Scope of QPN in ARP Request

From: "Larsen, Roy K" <[email-masked]>
Date: Mon, 28 Jan 2002 10:33:13 -0800

In the Ethertype thread, it was implied by some that the QPN could be used
to demultiplex all protocols carried by IPoIB.  For this to be true, nodes
receiving the ARP request broadcast can not assume that the source link
address is the destination link address for IPv4 frames.  That is, it is
only guaranteed to accept ARP replies.

The encapsulation draft must be clear on the scope of the QPN carried in an
ARP request.  If it only specifies the ARP reply queue, then a single ARP
request/reply transaction can not identify both IPv4 endpoints.

Since limiting the scope of the QPN in this way would double ARP traffic, I
would like to propose the encapsulation draft state that the QPN specified
in the ARP request source hardware address MUST be able to except all ARP
and IPv4 protocol frames.

Roy

_______________________________________________
IPoverIB mailing list
[email-masked]
https://www1.ietf.org/mailman/listinfo/ipoverib

---

From: Vivek Kashyap <[email-masked]>
Date: Mon, 28 Jan 2002 10:56:11 -0800 (PST)

> and IPv4 protocol frames.

Yes, that is correct. The QPN included in the ARP request/reply MUST
accept both IPv4 and ARP packets in IBA's unreliable mode. Otherwise
we need to exchange two QPNs or exchange two messages.

Vivek

-- 
Vivek Kashyap
Linux Technology Center, IBM
[email-masked] 
[email-masked] 
503 578 3422 (o)