T1 occasional high-latency

hack.bac · Guest

I have a T1 Internet connection that occasionally gets 200+ ms
delays. (See below.) This is a recurring problem that I anticipate
will be detrimental to VoIP.

What would cause these instances of high-latency?
I have worked with the ISP and have not found anything unusual. This
occurs both during peak hours and off-peak hours. Bandwidth
utilization on this link is minimal. Short BERTs show a clean line.
CPU utilization on both routers are also minimal (0% and 5%). My
router is a Cisco 7206VXR using T1 modules, and I believe the ISP
gateway is a 3600 series router with an external CSU/DSU.

! Extended ping to the T1 gateway
Sending 10000, 100-byte ICMP Echos to ---.---.---.201, timeout is 2
seconds:
Reply to request 0 (1 ms)
Reply to request 1 (4 ms)
Reply to request 2 (1 ms)
Reply to request 3 (4 ms)
Reply to request 4 (1 ms)
Reply to request 5 (4 ms)
Reply to request 6 (4 ms)
Reply to request 7 (1 ms)
Reply to request 8 (4 ms)
Reply to request 9 (1 ms)
Reply to request 10 (4 ms)
.......................................
Reply to request 74 (4 ms)
Reply to request 75 (104 ms)
Reply to request 76 (1 ms)
.......................................
Reply to request 170 (4 ms)
Reply to request 171 (24 ms)
Reply to request 172 (1 ms)
Reply to request 173 (4 ms)
Reply to request 174 (4 ms)
Reply to request 175 (1 ms)
Reply to request 176 (220 ms)
Reply to request 177 (220 ms)
Reply to request 178 (204 ms)
Reply to request 179 (204 ms)
Reply to request 180 (204 ms)
Reply to request 181 (204 ms)
Reply to request 182 (200 ms)
Reply to request 183 (200 ms)
Reply to request 184 (200 ms)
Reply to request 185 (200 ms)
Reply to request 186 (200 ms)
Reply to request 187 (84 ms)
Reply to request 188 (4 ms)
Reply to request 189 (1 ms)
Reply to request 190 (4 ms)
.......................................
Reply to request 6924 (1 ms)
Reply to request 6925 (224 ms)
Reply to request 6926 (220 ms)
Reply to request 6927 (220 ms)
Reply to request 6928 (220 ms)
Reply to request 6929 (220 ms)
Reply to request 6930 (208 ms)
Reply to request 6931 (200 ms)
Reply to request 6932 (208 ms)
Reply to request 6933 (200 ms)
Reply to request 6934 (204 ms)
Reply to request 6935 (200 ms)
Reply to request 6936 (200 ms)
Reply to request 6937 (76 ms)
Reply to request 6938 (1 ms)
Reply to request 6939 (4 ms)
Reply to request 6940 (4 ms)
.......................................
Reply to request 9999 (1 ms)
Success rate is 100 percent (10000/10000), round-trip min/avg/max =
1/3/224 ms