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New Visitor
Posts: 3
Registered: ‎08-13-2005

What is an acceptable packet loss for a COMCAST high speed connection?

Hi,

I've just moved from Colorado to New Mexico, and had to change cable providers. The performance of the network connection from New Mexico is visibly slower than my previous experience. Besides a slower performance to paint internet pages, there are frequent needs to refresh the browser image because the first attempt to retrieve a page has failed.

Below are the 5 pieces of data you requested before you can investigate a reported connection issue. Based on this data I believe a starting point for the investigation would be to establish a baseline for packet loss since I imagine the symptoms I'm experiencing are due to the packet loss, e.g. 23% in the ping test included below.

Thanks for any help you can provide.

Robin

1)****************************
C:\Documents and Settings\robin>tracert www.comcast.net

Tracing route to www.comcast.net
over a maximum of 30 hops:

1 3 ms 3 ms 3 ms 192.168.1.1
2 9 ms * * 10.96.8.1
3 * 10 ms 9 ms 68.86.206.129
4 14 ms 13 ms 13 ms 68.86.206.150
5 * 14 ms * 68.35.172.50
6 23 ms 25 ms 23 ms 12.127.141.65
7 51 ms * * gbr1-p80.phmaz.ip.att.net
8 45 ms * * gbr1-p30.sd2ca.ip.att.net
9 50 ms * 49 ms gbr2-p60.sd2ca.ip.att.net
10 * 46 ms 47 ms tbr2-p012202.la2ca.ip.att.net
11 46 ms 45 ms * gar4-p390.la2ca.ip.att.net
12 53 ms 55 ms 53 ms idf26-gsr12-1-pos-6-0.rwc1.attens.net
13 * * 53 ms rwcsbix12-1-4.attbi.com
14 * * * Request timed out.
15 * * 53 ms www.comcast.net

Trace complete.

2)***********************************************
C:\Documents and Settings\robin>ping -t www.comcast.net

Pinging www.comcast.net with 32 bytes of data:

Reply from 204.127.205.8: bytes=32 time=69ms TTL=49
Reply from 204.127.205.8: bytes=32 time=77ms TTL=49
Reply from 204.127.205.8: bytes=32 time=69ms TTL=49
Reply from 204.127.205.8: bytes=32 time=71ms TTL=49
Reply from 204.127.205.8: bytes=32 time=68ms TTL=49
Request timed out.
Reply from 204.127.205.8: bytes=32 time=69ms TTL=49
Reply from 204.127.205.8: bytes=32 time=68ms TTL=49
Reply from 204.127.205.8: bytes=32 time=77ms TTL=49
Reply from 204.127.205.8: bytes=32 time=70ms TTL=49
Request timed out.
Reply from 204.127.205.8: bytes=32 time=69ms TTL=49
Reply from 204.127.205.8: bytes=32 time=69ms TTL=49
Reply from 204.127.205.8: bytes=32 time=70ms TTL=49
Request timed out.
Reply from 204.127.205.8: bytes=32 time=69ms TTL=49
Reply from 204.127.205.8: bytes=32 time=68ms TTL=49
Reply from 204.127.205.8: bytes=32 time=69ms TTL=49
Reply from 204.127.205.8: bytes=32 time=69ms TTL=49
Reply from 204.127.205.8: bytes=32 time=68ms TTL=49
Reply from 204.127.205.8: bytes=32 time=68ms TTL=49
Reply from 204.127.205.8: bytes=32 time=70ms TTL=49
Reply from 204.127.205.8: bytes=32 time=71ms TTL=49
Request timed out.
Reply from 204.127.205.8: bytes=32 time=69ms TTL=49
Request timed out.
Request timed out.
Request timed out.
Reply from 204.127.205.8: bytes=32 time=69ms TTL=49
Reply from 204.127.205.8: bytes=32 time=72ms TTL=49
Request timed out.
Request timed out.
Reply from 204.127.205.8: bytes=32 time=81ms TTL=49
Reply from 204.127.205.8: bytes=32 time=69ms TTL=49
Request timed out.
Reply from 204.127.205.8: bytes=32 time=80ms TTL=49
Reply from 204.127.205.8: bytes=32 time=69ms TTL=49
Reply from 204.127.205.8: bytes=32 time=68ms TTL=49
Reply from 204.127.205.8: bytes=32 time=68ms TTL=49
Reply from 204.127.205.8: bytes=32 time=70ms TTL=49
Reply from 204.127.205.8: bytes=32 time=69ms TTL=49
Request timed out.
Reply from 204.127.205.8: bytes=32 time=69ms TTL=49
Reply from 204.127.205.8: bytes=32 time=67ms TTL=49
Reply from 204.127.205.8: bytes=32 time=69ms TTL=49
Reply from 204.127.205.8: bytes=32 time=69ms TTL=49

Ping statistics for 204.127.205.8:
Packets: Sent = 46, Received = 35, Lost = 11 (23% loss),
Approximate round trip times in milli-seconds:
Minimum = 67ms, Maximum = 81ms, Average = 70ms
Control-C
^C

3)**************************************
Results from modem statistics page:
Receive Power Level
4.5 dBmV
Transmit Power Level
39.8 dBmV

4)***************************************
The symptoms occur through the day/evening, any day of the week.

5)****************************************
City: Las Cruces
State: New Mexico
Most Valued Poster
Posts: 7,447
Registered: ‎07-10-2003

Re: What is an acceptable packet loss for a COMCAST high speed connection?

It does look like a problem with your local connection. What's your receive SNR? Do a ping -t to your default gateway(get it from your router) to document the drops on your connection.
New Visitor
Posts: 7
Registered: ‎08-07-2005

Re: What is an acceptable packet loss for a COMCAST high speed connection?

I am currently seeing 5-15% routine packet loss in Federal Way, Washington state.
New Visitor
Posts: 5
Registered: ‎03-17-2004

Re: What is an acceptable packet loss for a COMCAST high speed connection?

FYI, I have been running between 30 and 50% packet loss in Plano, Texas for almost a month. Still waiting on a fix ("We're working on it").

n5xbs308.
New Visitor
Posts: 3
Registered: ‎08-13-2005

Re: What is an acceptable packet loss for a COMCAST high speed connection?

Thanks for your suggestion...

What does SNR stand for?

What command do I use to obtain the default gateway from the router?

Thanks
Most Valued Poster
Posts: 7,447
Registered: ‎07-10-2003

Re: What is an acceptable packet loss for a COMCAST high speed connection?

The SNR or Receive Signal to Noise ratio should be listed right near your signal power levels on the modem status page.

For the default gateway, go to you router's web interface at http://192.168.1.1. You may have to enter the default username/password given in your router's documentation. Then go to the router status page and look for WAN IP or Internet IP Address. Right under it should be listed the IP of the default gateway. This is the first router past your modem. You can the the IP 10.96.8.1 too, which goes to the same router, but you should use the public IP of the default gateway, since that's what your router uses.
Bronze Star Contributor
Posts: 151
Registered: ‎09-18-2003

Re: What is an acceptable packet loss for a COMCAST high speed connection?

The router MAY be @ 192.168.1.1. Some routers have a default LAN IP address of 192.168.0.1 (I know actiontec and D-Link are this way).

An easier way would be to run a tracert from the command prompt. The gateway should be your first pingable hop outside your LAN.
Most Valued Poster
Posts: 7,447
Registered: ‎07-10-2003

Re: What is an acceptable packet loss for a COMCAST high speed connection?

> The router MAY be @ 192.168.1.1. Some routers have a
> default LAN IP address of 192.168.0.1 (I know
> actiontec and D-Link are this way).

1 3 ms 3 ms 3 ms 192.168.1.1
2 9 ms * * 10.96.8.1
3 * 10 ms 9 ms 68.86.206.129

> An easier way would be to run a tracert from the
> command prompt. The gateway should be your first
> pingable hop outside your LAN.

Yes it is, but the tracert(see above) gives the private IP of the gateway. You should use the public IP.
Bronze Star Contributor
Posts: 151
Registered: ‎09-18-2003

Re: What is an acceptable packet loss for a COMCAST high speed connection?

On all trace routes I run, I get something like this:

192.168.1.1 -> * -> 68.86.105.21

The second hop always times out. So, I ping -n the first pingable IP outside my router. TBH, I have never seen a pingable hop directly behind the router, it always times out.

His local config must be setup differently than mine - I have never seen Comcast private gateways as being pingable - even from their own network.
New Visitor
Posts: 3
Registered: ‎08-13-2005

Re: What is an acceptable packet loss for a COMCAST high speed connection?

Thanks.

When I select the Status option on the modem site (http://192.168.100.1) it says "This feature is not enabled. Please contact your data services provider for more information about this feature and its availability on the network.".

I only have access to the System option, which doesn't show Signal to Noise Ratio. Only the Receive and Transmit power levels are displayed on the System page.

The modem is a Webstar, Scientific Atlanta.
Most Valued Poster
Posts: 7,447
Registered: ‎07-10-2003

Re: What is an acceptable packet loss for a COMCAST high speed connection?

Areas are set up differently. For the most part gateways are pingable, the areas that are not seem to be the exception. That's unfortunate since it enables you to separate the RF connection segment from the routable network to aid in troubleshooting. The gateway IP started to become visible to ICMP traffic in attbi areas soon after the merger. In general, if the public IP is pingable, so the private one.
Most Valued Poster
Posts: 7,447
Registered: ‎07-10-2003

Re: What is an acceptable packet loss for a COMCAST high speed connection?

That modem is an OEM version with limited info. There are other password protected pages, but they may be disabled. You could call tech support to get the SNR reading remotely.
Bronze Star Contributor
Posts: 151
Registered: ‎09-18-2003

Re: What is an acceptable packet loss for a COMCAST high speed connection?

Weird.

Every trace route I do goes as above - 68.86.105.21 being the first non-lan pingable IP.

When looking @ my router, the default gateway is 67.76.21.149 (which I can ping here from work).

So, I take it that 68.86.105.21 is the "public" ip for my gateway and 67.76.21.149 is the "private" ip for the gateway?

If it's private, how can I ping it from work using DSL? I have never seen the 67.76.21.149 in any trace route before.

I'm asking not be be a a smart a$$, but because I truly don't know.
Most Valued Poster
Posts: 7,447
Registered: ‎07-10-2003

Re: What is an acceptable packet loss for a COMCAST high speed connection?

Are you sure the 67.76.21.149 IP is in your router? That goes to oh-67-76-21-149.sta.sprint-hsd.net, not a comcast address. Gateway IPs always look like 68.86.xx.1, where the first two octets are the same as your IP. Sometimes the last number is 129, but that's rare.

The 68.86.105.21 IP is the first local router after the default gateway. In your case, the gateway times out because ICMP response is turned off. Normally, you can ping the public gateway IP from outside the network, but not the private IP. From home, you can ping both, but not in your case.

To see if you can ping your Comcast IP, assigned to the router, have someone from your home PC go to http://whatismyip.com and get the IP number.

Private IPs are reserved for internal network use and are not routable outside the network. They always look like 10.xx.xx.xx, 192.168.xx.xx, and 172.16.xx.xx. Because they are not routable, they can be reused in different locations without conflict. For example, virtually everyone's home router is 192.168.0.1. or 192.168.1.1.
Bronze Star Contributor
Posts: 151
Registered: ‎09-18-2003

Re: What is an acceptable packet loss for a COMCAST high speed connection?

My mistake - I had several typos on that one...

My router (the only DHCP client connected to my cable modem) IP address is 67.176.21.149 (the same IP given by ip chicken and other services like that). My default gateway is 67.176.16.1 (as listed in my router's status page).

Both go to hsd1.co.comcast.net here in Denver (according to Neotrace).

Only 67.176.16.1 is pingable here from work.

Regardless, I have never seen 67.XXX.XXX.XXX in any trace route exiting my home connection. The first non-LAN hop is ALWAYS 68.86.XXX.XXX.

I have been having connection issues for literally 4 months where I see 700 milliseond pings to 68.86.105.21 - the first IP address (other than a 192.XXX.XXX.XXX address) outgoing in any tracert. I have assumed that this was the gateway, but it appears it's one hop after the gateway (assuming 67.176.16.1 is my gateway as listed in my router). I will see if I get the same horrible latency to 67.176.16.1 as I do to 68.86.105.21.
Most Valued Poster
Posts: 7,447
Registered: ‎07-10-2003

Re: What is an acceptable packet loss for a COMCAST high speed connection?

> Only 67.176.16.1 is pingable here from work.

That's good. Chances are that it's pingable from home too. Maybe only the private IP is not. It's hard to say because inbound and outbound connections are made through different ports on the router. If it is pingable, you should also get a two hop tracert, first to your router and then your gateway, where the 2nd hop timeout is now.

You can't ping your Comcast IP, the router WAN IP, because you probably have it turned off in the router setup. The 700 ms pings to the 3rd hop is terrible. If you get the same thing to the 2nd hop gateway, you know it's the local RF cable segment connection. If that's good and it occurs between the gateway and the next router, then it's a network congestion problem or malfunctioning router. You should also ping your modem at 192.168.100.1 to check out everything up to cable segment. That won't normally show up on a tracert because the modem is a protocol bridge. But it will respond to pings directly.
Bronze Star Contributor
Posts: 151
Registered: ‎09-18-2003

Re: What is an acceptable packet loss for a COMCAST high speed connection?

I can ping my (according to my router) local gateway from home as well:

>ping 67.176.16.1

Pinging 67.176.16.1 with 32 bytes of data:

Reply from 67.176.16.1: bytes=32 time=82ms TTL=63
Reply from 67.176.16.1: bytes=32 time=32ms TTL=63
Reply from 67.176.16.1: bytes=32 time=63ms TTL=63
Reply from 67.176.16.1: bytes=32 time=11ms TTL=63

Ping statistics for 67.176.16.1:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 11ms, Maximum = 82ms, Average = 47ms

As you can see, the times are horrible. This should average about 8 milliseconds. In about 3 hours, these times will increase by an order of magnitude.

Here's a trace route:

>tracert www.comcast.net

Tracing route to www.comcast.net
over a maximum of 30 hops:

1 2 ms 2 ms 2 ms 192.168.1.1
2 * * * Request timed out.
3 12 ms 35 ms 30 ms 68.86.105.21
4 41 ms 24 ms 136 ms 68.86.103.101
5 17 ms 21 ms 12 ms 68.86.103.1
6 60 ms 14 ms 15 ms 68.86.103.134
7 58 ms 15 ms 16 ms 12.124.158.17
8 50 ms 49 ms 66 ms gbr2-p60.dvmco.ip.att.net
9 50 ms 50 ms 50 ms gbr1-p60.cb1ma.ip.att.net
10 52 ms 54 ms 84 ms tbr1-p012402.cgcil.ip.att.net
11 54 ms 59 ms 53 ms tbr1-cl1.n54ny.ip.att.net
12 139 ms 54 ms 52 ms gbr1-p10.n54ny.ip.att.net
13 50 ms 49 ms 76 ms gar1-p360.n54ny.ip.att.net
14 60 ms 57 ms 86 ms mdf1-gsr12-2-pos-7-0.nyc3.attens.net
15 147 ms 71 ms 54 ms 63.240.64.102
16 * * * Request timed out.
17 * * * Request timed out.
18 57 ms 56 ms 126 ms www.comcast.net

Trace complete.

As you can see, it's 68.86.105.21 after the modem. The only reference to 67.XXX.XXX.XXX is in my router....

Here's a ping to my modem (over my wifi on my laptop - not as good as my normal connection):

>ping -t 192.168.100.1

Pinging 192.168.100.1 with 32 bytes of data:

Reply from 192.168.100.1: bytes=32 time=3ms TTL=254
Reply from 192.168.100.1: bytes=32 time=3ms TTL=254
Reply from 192.168.100.1: bytes=32 time=3ms TTL=254
Reply from 192.168.100.1: bytes=32 time=3ms TTL=254
Reply from 192.168.100.1: bytes=32 time=3ms TTL=254
Reply from 192.168.100.1: bytes=32 time=3ms TTL=254
Reply from 192.168.100.1: bytes=32 time=3ms TTL=254
Reply from 192.168.100.1: bytes=32 time=3ms TTL=254

Ping statistics for 192.168.100.1:
Packets: Sent = 8, Received = 8, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 3ms, Maximum = 3ms, Average = 3ms

As you can see, there are no 800 millisecond spikes on my LAN.

After 1/3 of a year of complaints and 5 technicians, Comcast is set to re-route some traffic off my node this Thursday.

Considering my connection becomes literally 100 times slower @ peak times, it has always made sense that I'm connected to a saturated node. The supervisor I talked with (after banging my head with the front-end support people for 3 months and about 25 phone calls) told me there were indeed too many people connected to my node.

Anyway, I'm not sure why the gateway IP times out on a trace route...
Connection Expert
EG
Posts: 43,788
Registered: ‎12-24-2003

Re: What is an acceptable packet loss for a COMCAST high speed connection?

>>Anyway, I'm not sure why the gateway IP times out on a trace route...

Some of these are set up, not to respond to ICMP packets.
Bronze Star Contributor
Posts: 151
Registered: ‎09-18-2003

Re: What is an acceptable packet loss for a COMCAST high speed connection?

I guess I will need some explanation on the difference between pinging and trace routing.

I can ping 67.176.16.1 but it's nowhere to be found during a trace route.
Most Valued Poster
Posts: 7,447
Registered: ‎07-10-2003

Re: What is an acceptable packet loss for a COMCAST high speed connection?

> ping 67.176.16.1
>
> Minimum = 11ms, Maximum = 82ms, Average = 47ms
>
> As you can see, the times are horrible. This should
> average about 8 milliseconds. In about 3 hours, these
> times will increase by an order of magnitude.

Yes, they are bad. There may be a reason ping is turned off in the gateway for the IP that time out.:smileywink:


> 18 57 ms 56 ms 126 ms www.comcast.net
> t

Your latency to the east coast is good, but it's erratic, probably from your 2nd hop troubles.

> As you can see, it's 68.86.105.21 after the modem.
> The only reference to 67.XXX.XXX.XXX is in my
> router....

Well it's not really after the modem. There is a router after the gateway, it just doesn't answer. So after three tries, the PC trace utility goes on to the next device in the path. It doesn't know the IP of that hop because of the way tracert works.

Your router has a public and private IP too. Your PC only sees the private one on the LAN side. The internet only sees the public one on the WAN side. But they are the same device on the same hop.

> Ping statistics for 192.168.100.1:
> Packets: Sent = 8, Received = 8, Lost = 0 (0%
> (0% loss),
> Approximate round trip times in milli-seconds:
> Minimum = 3ms, Maximum = 3ms, Average = 3ms

Everything's good to your modem.

> As you can see, there are no 800 millisecond spikes
> on my LAN.

Nope. Everything's fine.

> After 1/3 of a year of complaints and 5 technicians,
> Comcast is set to re-route some traffic off my node
> this Thursday.

That'll help.

> Considering my connection becomes literally 100 times
> slower @ peak times, it has always made sense that
> I'm connected to a saturated node. The supervisor I
> talked with (after banging my head with the front-end
> support people for 3 months and about 25 phone calls)
> told me there were indeed too many people connected
> to my node.
>
> Anyway, I'm not sure why the gateway IP times out on
> a trace route...

The answer you got from the supervisor may be why. When you can see it, you can isolate it and do something about it.:smileywink:
Most Valued Poster
Posts: 7,447
Registered: ‎07-10-2003

Re: What is an acceptable packet loss for a COMCAST high speed connection?

The ping utility sends an ICMP packet to a particular IP, and it is routed to the final destination where it is timestamped and returned.

The tracert utility sends an ICMP packet with a destination IP. But it also contains a TTL parameter which specifies how many hops the packet is allowed to be forwarded before it must be returned. Each router examines the packet, and if it is the last hop permitted, it timestamps it and sends it back with it's own IP as the source IP. The utility sends three packets to each hop, and then increments TTL by one each time until the final destination is reached. If any hop doesn't return it, the utility times out that hop and goes on. Since the packet wasn't returned, it doesn't know the IP of the device on that hop.
New Visitor
Posts: 1
Registered: ‎08-16-2005

Re: What is an acceptable packet loss for a COMCAST high speed connection?

I am having the same problem her in Dallas,Tx as Anon is in NM. I have had Comcast out to my house three times in the last 4 weeks! Its fustration and my high pocket loss is occuring at my drop,in which im 200 feet from it! They said its the closest conecting pole! I ahve pinged yahoo today and every 11 lines,it is showing a TIME OUT-
Im very unhappy with this its interupting the things I need to do online daily,not to mention,I have the same problem,where it boots me off during the day and night everyday........
I want this fixed,I pay liek everyone else alot of money to have ' High Speed ' Internet and this is worse than dial up. Im not happy-
Contributor
Posts: 24
Registered: ‎06-07-2005

Re: What is an acceptable packet loss for a COMCAST high speed connection?

Acceptable packet loss? HA! Thanks for the laugh. There is no such thing as acceptable packet loss.