Plan inter-company video calls through Expressway: search rules, SIP URI dial patterns, encryption policy, DNS/SRV records, and firewall/cert requirements for B2B interop.
B2B (business-to-business) video calling lets your endpoints dial SIP URIs at partner organizations (user@partner.com) through Expressway. This planner configures search rules, DNS, encryption, and firewall for secure interop with any SIP-reachable org — including room systems, Microsoft Teams (via Cloud Video Interop), and Google Meet.
Set inputs, click Plan B2B calling.
SRV for receiving B2B calls.
Rules to route outbound SIP URIs.
DNS zone for outbound lookup.
TLS, SRTP, ACL.
Known-good test URIs.
Inbound: when you@yourorg.com is called, the caller's Expressway looks up _sips._tcp.yourorg.com and/or _sip._tcp.yourorg.com in public DNS. These records should point to your Expressway-E. Publish TLS (5061) preferred, TCP (5060) as fallback. Skipping the SIP SRV records is the #1 reason inbound B2B fails — partners fall back to DNS A-record lookup which you don't control.
Outbound: your endpoint dials user@partner.com. On CUCM this matches the SIP URI dial pattern. CUCM forwards to Expressway-C via SIP trunk. Expressway-C has a search rule matching the partner domain (or .* for any) that forwards via Traversal zone to Expressway-E. Expressway-E uses its DNS zone to lookup _sips._tcp.partner.com, connect, and bridge media. If partner doesn't have SIP SRV, Expressway-E falls back to MX record, then A record.
Teams interop: Microsoft Teams does not natively support standard SIP B2B. You need either (a) a Cloud Video Interop gateway like Pexip, Poly RealConnect, or BlueJeans Gateway, or (b) Direct Routing with a SIP-aware SBC. Option (a) is the cleanest for organic calling; option (b) is more complex but gives you full control. Skype for Business federation rules are deprecated — do not rely on them in 2026+.
Traversal licenses on Expressway-E and RMS (Rich Media Session) for transcoding. No extra Cisco licensing for the pattern.
Yes — use Expressway-E CPL (Call Policy Language) rules or Search rule ACLs.
SIP video B2B doesn't use STIR/SHAKEN — that's voice/PSTN only. Rely on TLS cert validation.
Zoom has a SIP Connector — dial meetingid@zm.cisco.com or similar bridge URIs.
Supported via Pexip or Google's own SIP gateway. Dial format: meet-id@google.com.
Law firm calls our Webex Room.
Sales calls Teams room.
Integration with 3 partners.
Our UC Modernization Sprint brings up B2B video end-to-end: Expressway, CUCM routing, Teams interop, cert coord, and partner validation.