I recently updated from my previous speed to 50/10.
Since then the SMCD3G-CCR is having issues on regular basis :
- high ping shown in mtr or traceroute
- total loss of connectivity
- if we reboot the modem, only bond 2 upstream channels instead of 3
A technician came last week and was unable to find anything wrong. He suggested that my networking gear might be sending weird packet so I spent the whole weekend doing traffic capture (I mirrored the port on which the gateway is conencted on my cisco 3750 to another port and use wireshark to do a full traffic dump for a few hours from the mirrored port) and nothing weird shows in there, including when the problem occurs.
The SMCD3G-CCR seems to go wanky based on how much traffic is going thgough and now that bandwidth is higher than beffore there is more traffic going through.
To me it looks like the gateway has a hard time keeping up with the traffic and its cpu get overloaded and it crashes.
Anybody else has seem issue like this ?
And with all the issue I read about on the Netgear gateway I'd realy like to stick to the SMCD3G-CCR.
Could it be an error in the config file that the gateway download from the CMT ?
Welcome rpineau. Our Tier 2 agent verified has tested to the gateway and updated the service level to the gateway. Please retest and let us know if the issue persist.
I did more testing
As soon as I generate a fair amount of upstream traffic I see the ICPM packet getting dropped (I use mtr for my testing). Here is some mtr output from outside to my server.. see the packet loss as well as the huge ICMP RTT time on the 2 last ip which are the routed ip and the wan ip of the SMC gateway.
Packets Pings Host Loss% Snt Last Avg Best Wrst StDev 1. 192.168.240.1 0.0% 62 0.4 0.4 0.3 0.5 0.0 2. 18.104.22.168 0.0% 61 28.4 16.8 11.9 42.7 5.8 3. 22.214.171.124 0.0% 61 15.2 14.5 11.6 35.2 3.4 4. 126.96.36.199 0.0% 61 13.2 15.3 12.1 44.0 5.0 5. 188.8.131.52 0.0% 61 15.8 16.8 11.7 67.2 7.6 6. 184.108.40.206 0.0% 61 16.8 15.7 12.5 26.0 2.7 7. 220.127.116.11 0.0% 61 18.3 21.1 15.7 41.6 5.1 18.104.22.168 22.214.171.124 126.96.36.199 8. 188.8.131.52 0.0% 61 19.6 20.8 16.0 40.4 3.5 9. 184.108.40.206 0.0% 61 19.9 20.5 16.1 31.3 2.3 10. 220.127.116.11 0.0% 61 23.6 22.8 20.2 27.9 1.8 11. 18.104.22.168 0.0% 61 35.0 31.6 20.8 45.3 6.1 12. 22.214.171.124 1.6% 61 1204. 572.7 29.5 3671. 767.8 13. 126.96.36.199 1.6% 61 1120. 608.5 28.2 3608. 798.4
The lost packet % sometimes goes up over 80% and then I lose connectivity.
So it looks like there is still an issue.
I haven't lost connectivity today (yet) but I still see that high ping time issue.
Hi rpineau. Thank you for the additional info. As your post indicate the issue becomes more pronounced with increased traffic, the Comcast gateways does not a provide bandwidth management tool. To investigate further will require a service call to verify both the line and the equipment. Let us know if you a service call is requested.
When the tech came he already checked the line and found nothing wrong with it (very good signal, no noise).
I realy think it's either a hardware issue with the SMC gateway or a software/configuration issue introduced when I upgraded to 50/10.
Or may be the gateway doesn't have enough CPU power to actually do full routing at high speed as before the upgrade I never saw this problem.
I really don't want to change the SMC gateway for a netgear one in light of all the problems reported here and in other forum.
If I do some traceroute (using bot traceroute and mtr) it's obvious that the high ICMP response time is hapening inside the gateway between the wan ip and the headend (if the traceroute is done from inside we see the high response time on the gateway ip in my static block, if it's done from outside we see it on the wan ip just before my static which is also in the gateway as it's routed via RIPv2 to the wan ip).
I fully disabled all firewall feature as I have my how firewalls on 2 of the static IP (1 on my server and 1 on the cisco 2801 natting my internal machines and doing my IPv6 tunel). But to me it looks like the gateway is still doing something more that just routing the packet at this point and that's what could trigger the high ICMP response (and other issues on TCP session).
I once again had a total connectivity loss. I'm currently power cycling the gateway but I'd like a resolution on this asap as this is becoming a big issue for me.
Same issue again today at about the same time (11:20 yesterday, 11:39 today).
I rebooted the gateway and it took almost 10mn for it to start routing traffic again (getting the dhcp ip from the cmt on the wan side was not working ..).
So the problem happened again yesterday.
Comcast is going to send a tech tomorrow but I'm fairly sure they won't find anything like last time as they have no idea what the problem is and they tend to blame customer equipment ... all Cisco gears that don't change, config don't change.. the only thing that has changed is me upgrading to the premium 50 plan. That's when the problem started and it keeps reoccurring as soon has I have backups running (so cresting about 4Mbps constant upstream traffic).
So once again they won't find anything and will (again !!!) charge me $99 for a truck roll as they assume it's not from their equipment.
This is becoming really annoying (and costly). Comcast has really bad "business" gateway (there is nothing business about these cheap gateway besides the fact that they are running a specific Comcast firmware for the static IP routing).
Can someone at Comcast do some real debugging and figure out why traffic goes to hell when the gateway has "to much" upstream traffic ? This was not happening when I was on the previous plan and that's the ONLY thing that has changed.