A traversal client keeps a connection open through the firewall to a designated port on the traversal server using keepalives, and the server sends incoming call requests to the client over that connection.

Checked 2026-09-25

Vendor
Cisco
Product
Cisco Expressway
Subsystem
firewall traversal
Deployment
on-premises
Region
not restricted
Release range
X15.4
Checked
2026-09-25

Sources

Cite this note

APA

WarmTransfer. (2026, September 25). Expressway business-to-business calling: source note expressway-b2b-calling-traversal-mechanism. WarmTransfer. https://warmtransfer.net/knowledge/claims/expressway-b2b-calling-traversal-mechanism

BibTeX

@misc{warmtransfer-claim-expressway-b2b-calling-traversal-mechanism,
  title  = {Expressway business-to-business calling: source note expressway-b2b-calling-traversal-mechanism},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/claims/expressway-b2b-calling-traversal-mechanism},
  note   = {Source note expressway-b2b-calling-traversal-mechanism, checked 2026-09-25}
}

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