SIP trunk silliness after peering change


Does this make any sense? We (ASN 11579) peer to (2) WBS routers (ASN 19080).

We lost our link to the primary WBS router. After that, calls coming in over our SIP trunks were fine in one direction only. Callers could hear us, but we couldn't hear them. After 45 minutes, things righted themselves.

Later on the primary WBS link came back up and went down again 5 minutes later (not WBS's fault, we brought up and took down the BGP session).

Again we experienced the one-direction-only problem with, but this time it lasted 2.50 hours. Again things eventually righted themselves without our intervention.

Traces from us to were fine during the outage. We were unable to get a trace from to us during the outage. Maybe the only way to figure out what is going on is to get that return path trace during an outage.

Has anyone else experienced issues of this nature (extended outage of voice in one direction only) specifically with SIP trunks as a result of simply changing one's peering with one's upstream provider?