RE: [RPRWG] RPR Perf: Non-uniform distribution
Lewis,
How many other nodes are on your larger rings other than off-ring to core?
If ~128, then the pass-thru to add/drop ratio may be much higher than 80:20.
Can you share further information about traffic patterns in your own network
(destination address distribution)? 4 nodes connecting to the core could
spread traffic out (spatially) but may still constitute the hot spots on the
ring.
To Komal's question below, I'd like to see an access ring topology with no
more than 1 POP connection to core with 80% (or higher) of traffic destined
for it. I'd also like to see a topology with several points (4?) with an
equal likelihood of terminating the same amount of traffic that is likely to
go to the core (80% of total traffic, 1/N or 20% to each "core access
node"). This still assumes a lot of traffic is destined for comparatively
fewer nodes and is not uniformly distributed across all nodes. I would like
to hear others' suggestions on this.
--Jeff
Jeff Timbs
Agere Systems, Inc.
-----Original Message-----
From: Lewis Eatherton [mailto:leathert@xxxxxxxxxxxxxx]
Sent: Friday, April 27, 2001 12:06 AM
To: Komal Rathi
Cc: Timbs, Jeffrey L (Jeff); 'stds-802-17@xxxxxxxx'; seti@xxxxxxxxxxxxxx
Subject: Re: [RPRWG] RPR Perf: Non-uniform distribution
Actually, in several of our larger rings, we currently have 2 to 4 points
with
connections to our core. With most LEC infrastructure being OC48, I can
only
see this trend continuing. On the other hand, in most major markets, there
is
only one POP (depending on who your long haul connection is). (just the
@Home 2
cents)
Komal Rathi wrote:
> Hi Jeff,
>
> I agree with you that there will probably not be high multi-homing within
a
> MAN ring in the near term. A more realistic scenario will most likely be 2
> or more hubs (POPs) on the ring and unequal traffic going "off-ring" at
each
> hub. Do you have any suggestions for a set of realistic non-uniform
traffic
> patterns?
>
> Thanks,
> Komal
>
> -----Original Message-----
> From: Timbs, Jeffrey L (Jeff) [mailto:timbs@xxxxxxxxx]
> Sent: Thursday, April 26, 2001 6:04 AM
> To: 'stds-802-17@xxxxxxxx'
> Subject: RE: [RPRWG] RPR Perf: Non-uniform distribution
>
> Khaled et al:
> I agree with Komal's suggestion below. I would like to see the behavior
when
> a large % of traffic goes "off-ring" through few (1 or 2) nodes. It has
been
> reported that pass-thru : add/drop traffic is higher than 80:20 due to the
> long-distance nature of IP traffic. [Rodriguez-Moral et al, "Optical Data
> Networking," Journal of Lightwave Technology, Vol. 18, No. 12, December
> 2000] A further implication is that most IP traffic is not terminated
within
> a MAN, leading to hot-nodes (or gateways) which are destinations of the
> majority of traffic. Assuming that MAN rings are connected to backbone
> networks via few (one or two) nodes, a high percentage of traffic will be
> destined for these few nodes.
>
> Some interesting points are that, of 100 "leading" websites, WorldCom
could
> carry traffic to up to 45 of them entirely on its own backbone while MCI
> could reach 28 sites directly (Sprint, 18 sites). Also, 35 of the sites
> were multi-homed on the WorldCom backbone. [cf. OECD pub
> DSTI/ICCP/TISP(98)7/FINAL via
http://www.oecd.org/dsti/sti/it/cm/index.htm]
>
> It's not clear that there would be a high degree of multi-homing within a
> MAN ring (an economical factor driven by localized demand). For a high
> degree of destination stripping distributed across many nodes, several
> services would need to be offered at many sites (POPs). To me, there is a
> current assumption that new service providers want to populate as few POPs
> as possible, so that traffic must be carried to a centrallized site within
a
> region which also decreases the likelihood of uniform distribution.
>
> For near-term introduction of RPRs, we should consider that this traffic
> pattern may be more representative of a MAN RPR and should consider the
> impact on performance (due to lower overall spatial reuse).
>
> Jeff Timbs
> Agere Systems, Inc.
>
> -----Original Message-----
> From: Komal Rathi [mailto:krathi@xxxxxxxxxxxxxx]
> Sent: Tuesday, April 24, 2001 1:50 PM
> To: 'stds-802-17@xxxxxxxx'
> Subject: [RPRWG] RPR Perf: Non-uniform distribution
>
> Khaled and members of the Perf. Adhoc committee,
>
> Given that all implementations seem to have destination stripping that
> results in spatial reuse, it's not clear in my mind what we gain out of
> running simulations with randomly and uniformly distributed
> source/destination pairs. I believe that the uniform distribution will not
> provide enough information that would help demonstrate the differences in
> performance characteristics of various proposed architectures. All it does
> is show that we get some spatial reuse, which we know all implementations
> do.
>
> I would like to suggest that we make the destination addresses distributed
> non-uniformly which can show some more interesting performance
> characteristics of various architectures that are being proposed. For
> example, how about something like 80% to dest-A and some other
distribution
> to other destination nodes. Another idea would be to have 90% to
neighboring
> node A, and 10% to the other neighboring node B.
>
> Komal Rathi
> Lantern Communications