[TelstraClear] Cable vlan segmentation / ARP reduction

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doppleganger

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#24224 18-Jul-2008 13:58

Just wanted to let people know we're making good progress on dealing to the ARP issue on the cable network.

We successfully completed migrating a pilot cmts in chch to the vlan segmented architecture Tuesday morning in the wee smalls. Arp levels pre migration were ~120pps, post migration it was ~0.2pps.... we saw 6 arps in the 30sec capture we performed after we'd finished up. Since the pilot migration ARP levels sky rocketed at peak time to a whopping 2, count them 1... 2 packets per second.

Needless to say we're quietly happy with the results.

We're going to be performing the chch mass migration monday morning (21/07) so expect an outage of upto 15mins sometime between 1am and 3am depending on where you are in chch. Once you come back you should see significantly less arp.

Following on from that we're aiming to do the pilot CMTS in Wellington on Thursday morning next week (24/07) and Wellingtons mass migration on the following Tuesday (29/7).

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#149179 18-Jul-2008 15:18

That's fantastic news.. I remember the good old days ~10 years ago when my cable modem light used to come on when I was using the internet and not when everybody else was!

rscole86

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#149181 18-Jul-2008 15:21

That is good to hear! Hopefully there are plans to improve international connections soon.

robsonde

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#149188 18-Jul-2008 15:46

can someone give us a more english version of that tech posting??

I know what APR is, why is it an issue??

it the bit "cmts in chch to the vlan segmented architecture" than means nothing to me.

I understand that it means they are going to tweek stuff and make the world happay but............

cyril7

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#149196 18-Jul-2008 16:07

Good stuff, you say Wellington, does that include Kapiti.

Cyril

Quidam

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#149285 18-Jul-2008 20:22

robsonde: can someone give us a more english version of that tech posting??

I know what APR is, why is it an issue??

it the bit "cmts in chch to the vlan segmented architecture" than means nothing to me.

I understand that it means they are going to tweek stuff and make the world happay but............

cmts = cabe modem termination system

Cable modem at one end (your house) and cmts at the other.

I believe
that a cmts services many cable modems, and in the case of telstra clear, they have a very high ratio -meaning many cable modems are bottlenecked into a single cmts (which has a single fast ethernet connection to the fibre network).

but the arp traffic issue is due to the fact that telstras netork is one giant vlan, meaning the arp traffic is rampant. By segmenting the network into multiple vlans, the arp traffic won't roam the entire network like it currently does.

I'll bet there is a whole lot more to the story (of telstras network woes) than that -but really, as consumers, all we really want is a stable; fast internet connection that doesn't lag/drop connections etc.

Why Telstra let things get so bad is the real question, isn't it.

"There is no way to Peace -Peace is the Way" (A. J. Muste)

sbiddle

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#149294 18-Jul-2008 20:43

Quidam: [I believe
that a cmts services many cable modems, and in the case of telstra clear, they have a very high ratio -meaning many cable modems are bottlenecked into a single cmts (which has a single fast ethernet connection to the fibre network).

This used to be the case but part of TCL's major network upgrade over recent months has been the deployment of new CMTS's

Quidam

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#149901 21-Jul-2008 15:05

sbiddle: This used to be the case but part of TCL's major network upgrade over recent months has been the deployment of new CMTS's

Are you sure of your facts about this? I understand (as per glassmans post) that there is a commitment to segment existing nodes into 2 or 4 way splits (with SOME nodes being done before Christmas) and also a comment that when DOCSIS 3 is implemented it will force CMTS upgrades to gigabit -but there was no timeframe on DOCSIS 3, which I imagine would also require modem upgrades to fully realise the benefits.

This suggests that most (if not all) CMTS connections are still fast ethernet, and thus likely to be easily bottlenecked.

"There is no way to Peace -Peace is the Way" (A. J. Muste)

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Ender

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#149932 21-Jul-2008 16:45

Re maxing out Fast Ethernet - nope, not a problem (for now :)

From the Docsis 3.0 thread, from Doppleganger:

Actually US docsis streams (as opposed to euro docsis ones) are 6Mhz wide and TCL run theres at qam256. Do the math and that comes to 42.88Mbps, take a chunk of that for overheads and the _realistic_ max throughput for a modem is ~38Mbps.

Each CMTS has 100Mbit feeding it but a max downstream of somewhere around 38Mbit, so there's no congestion happening there.

sbiddle

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#149935 21-Jul-2008 16:53

I didn't mean "new" as in replacing all of them but new as in additional new CMTS's.

mattbush

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#149982 21-Jul-2008 19:40

Thanks heaps for the update.
I have been annoying the Sales people as to progress.

Whilst the internet costs are being refunded to me because i cannot game during peak hours in Wellington, I sincerely hope that this fixes the issue or you will see a mass migration to ADSL.

We need decent competition, but since late last year the Telstra situation has been very sad in certain parts of NZ.

I hope Wellington goes smooth....just wish you could bring it forward a week...LOL

Quidam

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#149993 21-Jul-2008 20:05

Ender: Re maxing out Fast Ethernet - nope, not a problem (for now :)

From the Docsis 3.0 thread, from Doppleganger:

Actually US docsis streams (as opposed to euro docsis ones) are 6Mhz wide and TCL run theres at qam256. Do the math and that comes to 42.88Mbps, take a chunk of that for overheads and the _realistic_ max throughput for a modem is ~38Mbps.

Each CMTS has 100Mbit feeding it but a max downstream of somewhere around 38Mbit, so there's no congestion happening there.

Ender, you do understand that there are potentially many modems attached to 1 cmts?!?

The issue is contention ratio, and unless someone from Telstra wants to say otherwise, Glassman admitted that by international standards we have loaded the nodes way over what is normally regarded as acceptable levels.

1 fast ethernet "is a bottleneck" if several people are online sucking from the same teet at the same time. Replace the cmts with a gigabit connection and the bottleneck is opened up significantly. Split the node into 2 or 4 and you also ease the bottleneck.

"There is no way to Peace -Peace is the Way" (A. J. Muste)

Quidam

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#149996 21-Jul-2008 20:15

sbiddle: I didn't mean "new" as in replacing all of them but new as in additional new CMTS's.

Thanks, but with this being the case, your comment is not much of a rebuttal to my original post, and I'm also well aware that you too have been getting less than steller performance right now

I have to say though, assuming the vlan segmentation happens soon (here in wellington) I hope we may see a significant improvement.

Fingers crossed.

"There is no way to Peace -Peace is the Way" (A. J. Muste)

cyril7

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#149997 21-Jul-2008 20:21

Quidam, each CMTS carrier can offer 36Mb/s to all subscribers its serves, so a 100Mb/s ethernet connection is not a bottleneck. What TCL are doing is reducing the number of subscribers per CMTS from somewhere like 2000 to 100. Guess the numbers talk for themselves, what you have to ask is why it has taken such an extreme contention ratio for TCL to stump up with the funds to improve the situation???

So maybe they were too busy raping the customers to realise how big the issues were.