Redundant ss7box Refinements

A redundant ss7box is being constructed in the lab once again with new twist to simulate an IP network with long and diverse links. We need to simulate the loss of an IP link between a remote Asterisk box and ss7box - something that will be more likely in a network that spans a very large region.  Using two distinctly different IP carriers for IP connections to each ss7box ensures link diversity.


In this new configuration we'll put in a small IP switch between the two mated ss7boxes and an Asterisk box. To test IP link loss we'll pull the IP cable between one of the ss7boxes and the IP switch. The result should be that the ss7box that lost the IP link should redirect the traffic to that IP  link to the crosslink to its mate ss7box, and the Asterisk box that lost the IP link should remap SLS to use its remaining in-service IP link to the other ss7box.  There will be a small window where signals could get lost during the transition. Calls with lost signals will timeout and be cleared. The call parties will experience abrupt call termination indications. Detecting loss of an IP link is  not as punctual as loss of SS7 link detection - IP is weak in this area. We'll help the situation by using a better ping-pong protocol on the IP links to indicate link loss.


The functionality described above does not exist yet, so we'll set up the test network; make test calls before making improvements and confirm that half of all calls will not complete when an IP link is lost; make appropriate code changes; run the call tests under IP link loss and restore conditions. We'll release this functionality in a major revision release - probably 2.7.


Here's a scan of the drawing we are using to build the lab network:

We use Google Doc spreadsheets for the configuration.


Progress:

1. The ss7 link between 1002 and the new mated 159 ss7box at 192.168.1.62 is up.
2. The SIP client on the Asterisk box on the 159 cluster has to be rebuilt. The laptop it was running on lost its HDD. The HDD was replaced and Mint 12 was installed last week. Was using Blink and XP previously.  Will need to find and test a suitable SIP client that works on Mint 12 and a Dell Vostro 1000.
   - looks like linphone is the first candidate; and it works too - tested on the 1003 node
3. write up the linphone and asterisk configuration

This is the link report from the 1002 ss7boxd that shows 3 ss7 links up:

Mar 15 11:34:27 ana156 ss7boxd[7056]: R:link util:ls 0:link 0:msu oc 26:tot oc 161840:util 0

Mar 15 11:34:27 ana156 ss7boxd[7056]: R:link util:ls 1:link 0:msu oc 34:tot oc 161840:util 0

Mar 15 11:34:27 ana156 ss7boxd[7056]: R:link util:ls 1:link 1:msu oc 34:tot oc 161920:util 0