[aodvv2-discuss] Re: AdvRte.Cost question

  • From: Lotte Steenbrink <lotte.steenbrink@xxxxxxxxxxxx>
  • To: aodvv2-discuss@xxxxxxxxxxxxx
  • Date: Tue, 23 Jun 2015 15:37:12 +0200

Hi Vicky,

Am 23.06.2015 um 15:00 schrieb Victoria Mercieca <vmercieca0@xxxxxxxxx>:

Hi Lotte,

Yes it's Cost(R) though we didnt refer to it this way. Do you think we should?


Personally, I think it would add clarity about what we're trying to do there
and would also help the kind of people who randomly search the document for
specific strings to figure things out (ahem, that would be me)... Currently,
when I run a text search for “Cost(R)” in the document to find out where route
costs are used, I can't find section 6.5. We could write something like

o AdvRte.Cost := Cost(R), i.e. AdvRte.Metric + Cost(L) using the cost
function
associated with the route's metric type, where L is the link from
the advertising router


what do you think?

Regards,
Lotte

Vicky.

On Tue, Jun 23, 2015 at 1:52 PM, Lotte Steenbrink
<lotte.steenbrink@xxxxxxxxxxxx> wrote:
Hi Vicky,

Am 23.06.2015 um 13:45 schrieb Victoria Mercieca <vmercieca0@xxxxxxxxx>:

Hi Lotte,

If A is sending a RREQ on behalf of OrigAddr, it will include hopcount
metric = 0 I thought. So when B gets that message, it sees zero, then adds
Cost(L) which is 1, so it stores route to OrigAddr with cost 1. It would
then advertise the cost of 1, so a router C (one hop further down the line)
would see advertised metric = 1, and would add cost of link from C to B to
get route cost of 2.


Right, so what we're calculating in 6.5. is actually Cost(R), isn't it?

So basically when sending a RREQ for a router client, you'd set metric to
zero.

Regards,
Vicky.

On Tue, Jun 23, 2015 at 12:40 PM, Lotte Steenbrink
<lotte.steenbrink@xxxxxxxxxxxx> wrote:
Hi all,
yet again, I'm not sure if I'm being stupid right now, but I think I've
found a misimplementation on my part and was wondering if it's just me or if
we should change the wording.. maybe one of you has the time to take a look:

Section 6.5. Processing Received Route Information says:
o AdvRte.Cost := AdvRte.Metric + Cost(L) using the cost function
associated with the route's metric type, where L is the link from
the advertising router
and then, section 6.5.2. Applying Route Updates says:

o Route.Metric := AdvRte.Cost

This (I think) has led me to implement my route table in a way that when I
have (very simplified) nodes A <-> B <-> ..., B's route table will say the
(hop count) metric for its connection to A is actually 2, since it takes the
Hop Count it learned from the RREQ and then adds another hop (namely
Cost(L)) onto it. This doesn't seem right to me; should I get another coffee
or is this an issue (i.e. if B's route table should have a metric of 1 for
the route towards A)?


Regards,
Lotte




Other related posts: