Cable Forum - View Single Post - 30M Le3 6

Chrysalis · 02-06-2011, 13:06

Well I now know why vmng300's have better jitter. Its nothing to with processing power but rather that they have lower queue's for upstream packets, in affect they given higher priority than other modems for timeslots. This can be a downside tho because if there is enough congestion and the max delay isnt high enough then there will be packetloss. Delay is better than packet loss.

Its only my guess as to why this jumps up and down tho, it seems to jump downwards less when utilisation is higher on the port. Also if utilisation is high enough even when its down the jitter will be as high as when it jumps upwards anyway. My guess is the modem operates differently in how it queues packets when under enough load. I think another way of putting it I think the queue size is dynamic, it possibly switches between a low bandwidth mode with a small queue and a high bandwidth mode with a large queue (higher jitter).

---------- Post added at 14:06 ---------- Previous post was at 12:51 ----------

starting to get rougher.

C:\Windows\system32>ping -n 10 194.168.4.100

Pinging 194.168.4.100 with 32 bytes of data:
Reply from 194.168.4.100: bytes=32 time=20ms TTL=252
Reply from 194.168.4.100: bytes=32 time=14ms TTL=252
Reply from 194.168.4.100: bytes=32 time=16ms TTL=252
Reply from 194.168.4.100: bytes=32 time=9ms TTL=252
Reply from 194.168.4.100: bytes=32 time=13ms TTL=252
Reply from 194.168.4.100: bytes=32 time=17ms TTL=252
Reply from 194.168.4.100: bytes=32 time=21ms TTL=252
Reply from 194.168.4.100: bytes=32 time=10ms TTL=252
Reply from 194.168.4.100: bytes=32 time=11ms TTL=252
Reply from 194.168.4.100: bytes=32 time=22ms TTL=252

Ping statistics for 194.168.4.100:
Packets: Sent = 10, Received = 10, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 9ms, Maximum = 22ms, Average = 15ms

on my tbb graph the modem gone into a low queue mode and can see its 50% higher max latency than last night at 10pm and its only 2pm.

seems also speedtest.net even with proxy is not close to 3mbit now either.

02-06-2011, 13:06	#18
Chrysalis cf.mega poster Join Date: Sep 2003 Posts: 12,048	Re: Le3 6 - network access denied? Well I now know why vmng300's have better jitter. Its nothing to with processing power but rather that they have lower queue's for upstream packets, in affect they given higher priority than other modems for timeslots. This can be a downside tho because if there is enough congestion and the max delay isnt high enough then there will be packetloss. Delay is better than packet loss. Its only my guess as to why this jumps up and down tho, it seems to jump downwards less when utilisation is higher on the port. Also if utilisation is high enough even when its down the jitter will be as high as when it jumps upwards anyway. My guess is the modem operates differently in how it queues packets when under enough load. I think another way of putting it I think the queue size is dynamic, it possibly switches between a low bandwidth mode with a small queue and a high bandwidth mode with a large queue (higher jitter). ---------- Post added at 14:06 ---------- Previous post was at 12:51 ---------- starting to get rougher. C:\Windows\system32>ping -n 10 194.168.4.100 Pinging 194.168.4.100 with 32 bytes of data: Reply from 194.168.4.100: bytes=32 time=20ms TTL=252 Reply from 194.168.4.100: bytes=32 time=14ms TTL=252 Reply from 194.168.4.100: bytes=32 time=16ms TTL=252 Reply from 194.168.4.100: bytes=32 time=9ms TTL=252 Reply from 194.168.4.100: bytes=32 time=13ms TTL=252 Reply from 194.168.4.100: bytes=32 time=17ms TTL=252 Reply from 194.168.4.100: bytes=32 time=21ms TTL=252 Reply from 194.168.4.100: bytes=32 time=10ms TTL=252 Reply from 194.168.4.100: bytes=32 time=11ms TTL=252 Reply from 194.168.4.100: bytes=32 time=22ms TTL=252 Ping statistics for 194.168.4.100: Packets: Sent = 10, Received = 10, Lost = 0 (0% loss), Approximate round trip times in milli-seconds: Minimum = 9ms, Maximum = 22ms, Average = 15ms on my tbb graph the modem gone into a low queue mode and can see its 50% higher max latency than last night at 10pm and its only 2pm. seems also speedtest.net even with proxy is not close to 3mbit now either.