Subject: Re: [Roll] routing metrics: available channels on a link/node

From: Mukul Goyal <[email-masked]>
Date: Tue, 19 May 2009 04:32:47 -0500 (CDT)

Hi JP,

In multi-channel operation, a node would be able to dynamically change the frequency range/channel it is using to communicate with other nodes. It may even be possible for a node to use multiple channels for communication (e.g. a mains-powered device with multiple radios). The objective for dynamic channel selection or multiple channel operation could be to improve reliability or relieve congestion.

The routing implication is that a node would not want to forward a packet to a neighbor on a channel that the neighbor is not listening to.

Thanks
Mukul

----- Original Message -----
From: "JP Vasseur" <[email-masked]>
To: "Mukul Goyal" <[email-masked]>
Cc: [email-masked]
Sent: Tuesday, May 19, 2009 4:00:57 AM GMT -06:00 US/Canada Central
Subject: Re: [Roll] routing metrics: available channels on a link/node

Hi Mukul,

On May 19, 2009, at 6:06 AM, Mukul Goyal wrote:

> I guess an important metric, for which I have seen no discussion so  
> far, is the channel(s) available (or being used) on a link/node. I  
> think multi-channel operation would emerge as a solution to many  
> problems as LLN-based applications become popular. Should we have  
> atleast some discussion of the "available channels on a link/node"  
> as a potential metric in the metrics draft?

The best way to answer this question is to have see the routing  
implication, how would you expect the routing protocol to use this  
information ?

Thanks.

JP.

>
> Thanks
> Mukul
>
> _______________________________________________
> Roll mailing list
> [email-masked]
> https://www.ietf.org/mailman/listinfo/roll

---

From: JP Vasseur <[email-masked]>
Date: Tue, 19 May 2009 11:36:57 +0200

Hi,

On May 19, 2009, at 11:32 AM, Mukul Goyal wrote:

> Hi JP,
>
> In multi-channel operation, a node would be able to dynamically  
> change the frequency range/channel it is using to communicate with  
> other nodes. It may even be possible for a node to use multiple  
> channels for communication (e.g. a mains-powered device with  
> multiple radios). The objective for dynamic channel selection or  
> multiple channel operation could be to improve reliability or  
> relieve congestion.
>

I know what multi-channel operation means, but my point was that a  
metric should be defined if and only if it is relevant to the routing  
protocol. If it translate to reliability, then it is a link  
reliability metrics, which could of course be used, not a metric that  
reflect the specific mechanism used by the L2, do you see my point ?

> The routing implication is that a node would not want to forward a  
> packet to a neighbor on a channel that the neighbor is not listening  
> to.

But then it is not a routing decision but a local forwarding one,  
handled locally by the transmitting node.

Thanks.

JP.