Cisco Cisco Expressway
External Network Elements
Jabber
An example remote endpoint, which is registering over the internet to Unified CM via the Expressway-E and
Expressway-C.
Expressway-C.
DNS (Host)
The DNS owned by service provider which hosts the external domain example.com.
DNS (external 1 & external 2)
The DNS used by the Expressway-E to perform DNS lookups.
NTP server pool
An NTP server pool which provides the clock source used to synchronize both internal and external devices.
NAT Devices and Firewalls
The example deployment includes:
■
NAT (PAT) device performing port address translation functions for network traffic routed from the internal
network to addresses in the DMZ (and beyond — towards remote destinations on the internet).
network to addresses in the DMZ (and beyond — towards remote destinations on the internet).
■
Firewall device on the public-facing side of the DMZ. This device allows all outbound connections and inbound
connections on specific ports. See
connections on specific ports. See
■
Home firewall NAT (PAT) device which performs port address and firewall functions for network traffic originating
from the EX60 device.
from the EX60 device.
■
See
with a static NAT and Dual Network Interface architecture.
SIP and H.323 Domain
The example deployment is configured to route SIP (and H.323) signaling messages for calls made to URIs which use
the domain example.com.
the domain example.com.
■
DNS SRV records are configured in the public (external) and local (internal) network DNS server to enable
routing of signaling request messages to the relevant infrastructure elements.
routing of signaling request messages to the relevant infrastructure elements.
■
The internal SIP domain (example.com) is the same as the public DNS name. This enables both registered and
non-registered devices in the public internet to call endpoints registered to the internal infrastructure.
non-registered devices in the public internet to call endpoints registered to the internal infrastructure.
.
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Cisco Expressway-E and Expressway-C - Basic Configuration Deployment Guide