Cisco Cisco TelePresence Video Communication Server Expressway 관리 매뉴얼
Protocols
VCS as a SIP proxy server
The VCS acts as a SIP proxy server when SIP mode is enabled. The role of a proxy server is to
forward requests (such as REGISTER and INVITE) from endpoints or other proxy servers on to further
proxy servers or to the destination endpoint.
forward requests (such as REGISTER and INVITE) from endpoints or other proxy servers on to further
proxy servers or to the destination endpoint.
The VCS's behavior as a SIP proxy server is determined by:
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the SIP registration proxy mode setting
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the presence of Route Set information in the request header
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whether the proxy server from which the request was received is a neighbor of the VCS
A Route Set specifies the path to take when requests are proxied between an endpoint and its
registrar. For example, when a REGISTER request is proxied by a VCS, the VCS adds a path header
component to the request. This signals that calls to that endpoint should be routed through the VCS.
This is usually required in situations where firewalls exist and the signalling must follow a specified
path to successfully traverse the firewall. For more information about path headers, see RFC 3327
[
registrar. For example, when a REGISTER request is proxied by a VCS, the VCS adds a path header
component to the request. This signals that calls to that endpoint should be routed through the VCS.
This is usually required in situations where firewalls exist and the signalling must follow a specified
path to successfully traverse the firewall. For more information about path headers, see RFC 3327
[
].
When the VCS proxies a request that contains Route Set information, it forwards it directly to the URI
specified in the path. Any call processing rules configured on the VCS are bypassed. This may
present a security risk if the information in the Route Set cannot be trusted. For this reason, you can
configure how the VCS proxies requests that contain Route Sets by setting the SIP registration
proxy mode as follows:
specified in the path. Any call processing rules configured on the VCS are bypassed. This may
present a security risk if the information in the Route Set cannot be trusted. For this reason, you can
configure how the VCS proxies requests that contain Route Sets by setting the SIP registration
proxy mode as follows:
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Off: requests containing Route Sets are rejected. This setting provides the highest level of security.
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Proxy to known only: requests containing Route Sets are proxied only if the request was received
from a known zone.
from a known zone.
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Proxy to any: requests containing Route Sets are always proxied.
In all cases, requests that do not have Route Sets are proxied as normal in accordance with existing
call processing rules. This setting only applies to dialog-forming requests, such as INVITE and
SUBSCRIBE. Other requests, such as NOTIFY, are always proxied regardless of this setting.
call processing rules. This setting only applies to dialog-forming requests, such as INVITE and
SUBSCRIBE. Other requests, such as NOTIFY, are always proxied regardless of this setting.
Proxying registration requests
If the VCS receives a registration request for a domain for which it is not acting as a Registrar (the
VCS does not have that SIP domain configured), then the VCS may proxy the registration request
onwards. This depends on the SIP registration proxy mode setting, as follows:
VCS does not have that SIP domain configured), then the VCS may proxy the registration request
onwards. This depends on the SIP registration proxy mode setting, as follows:
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Off: the VCS does not proxy any registration requests. They are rejected with a “403 Forbidden”
message.
message.
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Proxy to known only: the VCS proxies the request in accordance with existing call processing rules,
but only to known neighbor, traversal client and traversal server zones.
but only to known neighbor, traversal client and traversal server zones.
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Proxy to any: this is the same as Proxy to known only but for all zone types i.e. it also includes
ENUM and DNS zones.
ENUM and DNS zones.
Accepting proxied registration requests
If the VCS receives a proxied registration request, in addition to the VCS's standard
, you can also control whether the VCS accepts the registration depending upon the zone
through which the request was received. You do this through the Accept proxied registrations
setting when
setting when
.
Proxied registrations are classified as belonging to the zone they were last proxied from. This is
different from non-proxied registration requests which are assigned to a subzone within the VCS.
different from non-proxied registration requests which are assigned to a subzone within the VCS.
Cisco VCS Administrator Guide (X6.1)
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