Hello Pars, Response inline:
On 8/10/06 12:38 PM, "ext Pars MUTAF" <[EMAIL PROTECTED]> wrote: > Selon Basavaraj Patil <[EMAIL PROTECTED]>: > >> >> Inline: >> >> >> On 8/10/06 8:52 AM, "ext Pars Mutaf" <[EMAIL PROTECTED]> wrote: >> >>> >>> Hello, >>> >>> I'm still trying to understand the problem :-) >>> Unless I missed an episode, the context is >>> connection-oriented cellular networks under IP >>> (whatever that means) >>> >>> You say that the RA packets (unicasted) will wake up >>> 90% of hosts in the subnet. Because roughly %90 of >>> hosts are dormant, in general. >>> >>> I still believe that 30 minutes is longtime. Thus >>> the problem is not energy consumption perhaps >>> (without justification). >> >> 30 minutes is a long time. But if you have to go through the process of >> waking a host to simply deliver an RA, which in most instances has no value >> for the host, it is a waste of resources which include power, radio and >> possibly causing congestion as well. >> From a power consumption perspective: >> The host will wake up when paged and have to establish a traffic channel >> which requires it to request allocation of resources from the network. There >> is power that is consumed. Now if you argue that doing this every 30 minutes >> is not a problem...... I cant really argue against that. But my point is >> that why do you need to do this every 30 minutes in networks where you know >> that the host is not going to change the AR and the RA has no value to the >> host. >> >>> >>> But there is a problem if you link-layer page >>> many many hosts simultaneously to deliver an >>> RA. The paging channels may be saturated. From L2 >>> perspective, this would be similar to a situation >>> where many many cellular users are called >>> simultaneously, resulting in call setup delays. >>> Personally, I suspect that this may be a much more >>> serious problem than energy consumption. >> >> True. Paging a large number of dormant hosts simultaneously will be a >> serious issue for operators and people who do network planning don't like >> such broadcasts. So I agree that congesting the paging channel may be a more >> serious concern than power consumed by the host. >> Additionally you have to note that in order to deliver the RA you have to >> establish a traffic channel in most cases. Establishing this for a large >> number of hosts every 30 minutes just to deliver an RA is an overhead and >> waste of resources. >> >>> >>> But, firstly, your draft doesn't make it clear, >>> and secondly, I couldn't see how your draft solved >>> this problem. >> >> Solution is fairly simple as stated in the I-D: >> 1. Transmission of periodic RAs should be optional - It is a configurable >> parameter and the RA will indicate this to the host when it first attaches >> or solicits an RA. >> 2. Interval between periodic RAs should be flexible, i.e > 1800 secs. It is >> up to the deployment to determine what is an optimal interval. 1800 secs is >> just as random a value as 600 seconds or 5400 secs. >> >> And if a host needs an RA for some reason, it can always solicit it from the >> AR. > > > > This is the only point that needs clarification IMveryHO: > > Are the periodic RAs useless for those cellular hosts? Ignoring cellular hosts for a moment, how are periodic RAs useful for any host? RAs can be used as a means for detecting network attachment status or to detect movement (prefix change). In the case of a stationary host (as an example), periodic RAs really are of no benefit to the host (IMO). In certain cellular networks (GPRS/UMTS) the host does not change the AR (GGSN) that it is attached to frequently. In such cases there is no benefit of receiving the periodic RA. A cellular host such as a mobile phone does not need periodic Ras. However any laptop can also be considered as a cellular host when it connects to the cellular network. Hence you cannot generalize what a cellular host means. If you agree that movement detection and network attachment are not of serious concern in certain environments, what other reasons are there which makes the reception of the periodic RA critical? > > A periodic RA can periodically show me that the paging > subsystem still works, for example. I can sleep better. You don't verify today at regular intervals if the paging subsystem works and I am sure that is not causing any sleeplessness ;) So why would you worry about whether the system works or not? This is not required. Not at the IP layer at least. -Raj > > This makes sense in your context? (I'm not a > connection-oriented specialist). > > > >>> >>> The real solution, imho, is to distribute the >>> unicast RAs over time. For example, if there are >>> 5 hosts in the subnet and the RA period is 5 minutes, >> >> Staggered tranmission of RAs is one solution. There are others as well. > > > I'm curious what are the others? (if/when you have time) > > Thanks! > pars > > > >> >>> then >>> >>> start: >>> Min1 - send the 1st RA >>> Min2 - send the 2nd RA >>> ... >>> Min5 - send the 5th RA >>> >>> and goto start. >>> >>> This makes sense? Sorry if this is already specified >>> somewhere. >>> >>> Otherwise, you may want to filter the RAs at >>> the paging agent. >> >> Thanks for your comment. >> >> -Raj >> >>> >>> pars >>> >>> >>> >> >> > > > > > ---------------------------------------------------------------- > This message was sent using IMP, the Internet Messaging Program. -------------------------------------------------------------------- IETF IPv6 working group mailing list [email protected] Administrative Requests: https://www1.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
