Our supplier has our 550's on back order, so I can't comment specifically on the 550's. But this is the results with our Force300 PTP links with version 4.1.4-RC4 firmware. We get 3.5ms average latency.
10 packets transmitted, 10 received, 0% packet loss, time 9013ms rtt min/avg/max/mdev = 1.582/3.513/5.314/1.224 ms
Jumping from 1.5ms to 5.3ms is still more jitter than I'd like. But for us, the Force300's are nowhere near the 120ms that you guys are reporting. This 3.5ms average was with about 80 Mbit of client traffic going over the link.
PS. And this is the latency from the SM to the AP (8.4ms avg) while running a 20 second bandwith test from the AP to the SM to try to saturate the link. This link was passing about 310 mbps while doing this ping test.
rtt min/avg/max/mdev = 6.448/8.369/11.092/1.392 ms
As mentioned, while running the above 'ping' test, the link was carrying about 60 mbit of client traffic, plus the bandwidth test gave the following 'left over' results. Total was about 310 mbps aggregate traffic.
PING 10.0.0.45 (10.0.0.45) 32(60) bytes of data. 40 bytes from 10.0.0.45: icmp_req=1 ttl=64 time=8.24 ms 40 bytes from 10.0.0.45: icmp_req=2 ttl=64 time=6.44 ms 40 bytes from 10.0.0.45: icmp_req=3 ttl=64 time=8.69 ms 40 bytes from 10.0.0.45: icmp_req=4 ttl=64 time=6.65 ms 40 bytes from 10.0.0.45: icmp_req=5 ttl=64 time=9.54 ms 40 bytes from 10.0.0.45: icmp_req=6 ttl=64 time=8.07 ms 40 bytes from 10.0.0.45: icmp_req=7 ttl=64 time=8.28 ms 40 bytes from 10.0.0.45: icmp_req=8 ttl=64 time=6.94 ms 40 bytes from 10.0.0.45: icmp_req=9 ttl=64 time=11.0 ms 40 bytes from 10.0.0.45: icmp_req=10 ttl=64 time=9.68 ms— 10.0.0.45 ping statistics —
10 packets transmitted, 10 received, 0% packet loss, time 9015ms
rtt min/avg/max/mdev = 6.448/8.369/11.092/1.392 ms