Cambridge CMTS 17-2 / CMTS 15-2

[mhisani]

First of all this is a semi-cross post from a certain help and support forum from a certain popularly known ISP in these parts. I'm curious as for your options on the current state of play:

In November last year things nose dived on our connection in Trumpington, Cambridge and pings and packet loss were a mess most of the time. During peak times iplayer or even loading a website was impossible at times. It seems Virgin did some rebalancing or something a month or so ago and I ended up moving from CMTS 15-2 to CMTS 17-2 but things have been horrible. I keep being promised new dates and get different info from different teams.. Will this ever stop? The plan was to wait for CMTS 15-2 to get upstream 3 then get moved back but I can't get up to date info on this anymore either. Here is my TBB graph for the superhub:





https://www.cableforum.co.uk/images/local/2012/04/47.jpg

Now my parents who are also on 30mbit and are 2 miles away and ironically when I got moved off CMTS 15-2 to 17-2 they got moved from 14-2 to 15-2 and look at their TBB monitor:
https://www.cableforum.co.uk/images/local/2012/04/48.jpg



And also my brother who is also on CMTS 15-2 and hs been throughout:

https://www.cableforum.co.uk/images/local/2012/04/49.jpg


This baffles me...



Modem stats added:
Startup Procedure
Procedure Status Comment
Acquire Downstream Channel 299000000 Hz Locked
Connectivity State OK Operational
Boot State OK Operational
Configuration File OK
Security Enabled BPI+
Downstream Channels
Lock Status Modulation Channel ID Max Raw Bit Rate Frequency Power SNR Docsis/EuroDocsis locked
Locked QAM256 101 55616000 Kbits/sec 299000000 Hz -0.1 dBmV 41.6 dB Hybrid
Locked QAM256 99 55616000 Kbits/sec 283000000 Hz 0.1 dBmV 41.4 dB Hybrid
Locked QAM256 100 55616000 Kbits/sec 291000000 Hz -0.2 dBmV 41.5 dB Hybrid
Locked QAM256 102 55616000 Kbits/sec 307000000 Hz -0.6 dBmV 41.3 dB Hybrid
Locked QAM256 103 55616000 Kbits/sec 315000000 Hz 0.5 dBmV 41.3 dB Hybrid
Locked QAM256 104 55616000 Kbits/sec 323000000 Hz 0.1 dBmV 41.5 dB Hybrid
Unlocked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV 0.0 dB Unknown
Unlocked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV 0.0 dB Unknown
Upstream Channels
Lock Status Modulation Channel ID Max Raw Bit Rate Frequency Power
Locked ATDMA 4 20480 Kbits/sec 45800000 Hz 31.0 dBmV
Unlocked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
Unlocked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
Unlocked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV

Primary Downstream Service Flow
Downstream(0)
SFID 876
Max Traffic Rate 33330000 bps
Max Traffic Burst 3044 bytes
Mix Traffic Rate 0 bps
Primary Upstream Service Flow
Upstream(0)
SFID 875
Max Traffic Rate 3333000 bps
Max Traffic Burst 8160 bytes
Mix Traffic Rate 0 bps
Max Concatenated Burst 8160 bytes
Scheduling Type Best Effort

[boroboi]

Surely you'll still be on the same UBR?

I can clone my MAC and get a different IP address, i was im CMTS 16 in Teesside, then cloned a different MAC and i was on CMTS 2, maybe you can change the way you're routed but you can't change your UBR.

[mhisani]

Surely you'll still be on the same UBR?



They really did move me from 15 to 17 as a temp measure something about balancing while the work is done but still waiting.

[boroboi]

You literally can't be moved from one UBR to another from the flick of a switch, you're still on UBR 2, just on another range of IPs the way i understand it, possibly just routed differently, hmm

[mhisani]

You literally can't be moved from one UBR to another from the flick of a switch, you're still on UBR 2, just on another range of IPs the way i understand it, possibly just routed differently, hmm

... You obviously are unaware of how they can work allow me to copy the email I get from Virgin CEO office:

I checked my Virgin Email addy and they finally made some sense:

Hi REMOVED,

With regards to the information I can provide you with this is not much due to the business sensitivity however I can confirm CMTS 15 is receiving a new upstream, this will be the 3rd upstream however until this work is completed (due to end Mid April) the number of devices across the 3 CMTS in your area have been balanced to minimise the effect of utilisation.

Once the 3rd upstream has been completed you will be moved back to CMTS 15 where the service will be working correctly and the number of devices connected will be equally balanced.

I hope this information helps,

Kindest Regards,

REMOVED

NAMED REMOVED|Chief Executives Office
Virgin Media, PO Box 238, Wythenshawe, Manchester, M22 0WJ
CONTACT REMOVED| REMOVED@virginmedia.co.uk



24 Mar

to REMOVED

Understood.

So just to confirm the moving of some connections to CMTS 17-2 is until CMTS 15-2 has recieved new upsteam in the coming weeks and then I will be moved back to CMTS 15-2?


26 Mar

to me
Hi REMOVED,

I can confirm this is correct.


Best,


REMOVED

[Chrysalis]

none of the graphs are particurly good but I wonder if cmts 17 is also getting a new US as that sure needs it more than 15.

Interesting as well that the CEO office gave you that kind of info, usually I just get told something along the lines work is planned and thats it.

[mhisani]

When you complain to the ISPA 3 times and then mention the next step CISA they I guess start to start to have to think. And as for more US on 17 I suspect moving a load of people onto it who arent usually on 17 is causing a problem for others :(

Merry go round

[Sephiroth]

I noticed low upstream power (31.5).

If your event log contains a lot of T3 events, then there's an investigation required. You TBB graph (with its packet loss) is consistent with upstream issues.

As regards the UBR, it's the line card where congestion occurs not the UBR as a whole (generally).

[christopherw]

Apologies for the half-hijack ;) ... Suffering with upstream issues here too (wolv14 CMTS I believe).

Attempting to identify for certain the CMTS to do some monitoring; I don't have an overabundance of knowledge about how VM's network is currently laid out, where the CMTSes sit in their topology etc so I'm (re)learning as I go.

Is the simplest way to first resolve your gateway IP and go from there? Taking the current connection I'm using (cpc31-wolv14-2-0-custnn.16-1.cable.virginmedia.com), the connection gateway is cpc31-wolv14-2-0-gw.16-1.cable.virginmedia.com... which would make it CMTS wolv14?

Aside from either recursively searching the virginmedia.com DNS entries, do they all follow a standard format, e.g.

wolv-cmts-12-ge01.network.virginmedia.net
wolv-cmts-13-ge01.network.virginmedia.net
wolv-cmts-14-ge01.network.virginmedia.net

I've noticed parts of the hostnames can differ (e.g. ge02) so I'm assuming this simply denotes the inbound route (as the resolved IP is identical). Is there any way to monitor specific CPCs on the CMTS?

[Sephiroth]

You are on CMTS-14 at Wolverhampton. The "ge01" info refers to the type of port and port number (as in gigabit ethernet).

[christopherw]

You are on CMTS-14 at Wolverhampton. The "ge01" info refers to the type of port and port number (as in gigabit ethernet).

:tu:

Do you know if the CMTSes deprioritise ICMP?

[Sephiroth]

Yes it does when it has to.b