Ace - rtcp

ronald.spicka · ‎03-15-2011

Hi all,

I am looking for a rtsp solution, and currently i cann't find an answer.

The problem we got:

We are using a ace to loadbalance streaming traffic, which uses rtsp/rtcp.

rtsp is not a problem, simple vip on port 554 and forwarding to the servers.

but when it gets to rtcp it gets complicated

i configured a vip for udp high-ports, which works fine for messages from the client to the streamer.

but streaming data, which are sent from the server to the client , need to use the same source-ip as the vip

for that i created a nat-pool with the same ip as the vip.

so the ace takes all packets from the servers and creates a pat.

the thing is, that the clients get a problem with that.

within the rtsp-setup there is a negotation of ports to use.

if the source/ports, which are changed trough the pat, are different from the negotation, some clients wont work.

so the question is:

is there a way to do a pat with "fixed" ports, like: a port-range for server a, next range for server b and so on.

or is there a better solution for rtcp on the ace?

thanks a lot.

sachinga.hcl · ‎03-15-2011

ACE supports RTSP over TCP Loadbalanacing only.

You can use RTSP headers

RTSP stickiness is based on information in the RTSP session header. With RTSP header stickiness, you can specify a header offset to provide stickiness based on a unique portion of the RTSP header.

*Real Time Streaming Protocol (RTSP) is a network control protocol designed for use in entertainment and communications systems to control streaming media servers. The protocol is used to establish and control media sessions between end points.

(config) sticky rtsp-header

To create an RTSP header sticky group to enable the ACE to stick client connections to the same real server based on the RTSP Session header field, use the sticky rtsp-header command. The prompt changes to the sticky header configuration mode prompt (config-sticky-header). Use the no form of this command to remove the sticky group from the configuration.

sticky rtsp-header name1 name2

no sticky rtsp-header name1 name2
Syntax Description
name1
RTSP header field. The ACE supports only the RTSP Session header field for stickiness. Enter Session.

name2
Unique identifier of the sticky group. Enter an unquoted text string with no spaces and a maximum of 64 alphanumeric characters.

Command Modes

Configuration mode

Admin and user contexts
Command HistoryRelease Modification

A3(1.0)
This command was introduced.

Usage Guidelines

This command requires the sticky feature in your user role. For details about role-based access control (RBAC) and user roles, see the Cisco 4700 Series Application Control Engine Appliance Virtualization Configuration Guide.

To use the stickiness feature, you must allocate a minimum percentage of system resources to stickiness. Otherwise, the feature will not work. For more information about allocating resources, see the Cisco 4700 Series Application Control Engine Appliance Virtualization Configuration Guide.

The ACE supports only the RTSP Session header field for stickiness.

For information about the commands in RTSP sticky header configuration mode, see the "Sticky RTSP Header Configuration Mode Commands" section.
Examples

To create a group for RTSP header stickiness, enter:
host1/Admin(config)# sticky rtsp-header Session RTSP_GROUP
host1/Admin(config-sticky-header)#

To remove the sticky group from the configuration, enter:
host1/Admin(config)# no sticky rtsp-header Session RTSP_GROUP

Example of an RTSP Load-Balancing Configuration

http://docwiki.cisco.com/wiki/Cisco_Application_Control_Engine_(ACE)_Configuration_Examples_--_Server_Load-Balancing_Configuration_Examples#Example_of_an_RTSP_Load-Balancing_Configuration

As per cisco

http://www.cisco.com/en/US/docs/interfaces_modules/services_modules/ace/v3.00_A2/configuration/slb/guide/classlb.html#wp1165238

http://www.cisco.com/en/US/docs/app_ntwk_services/data_center_app_services/ace_appliances/vA3_1_0/configuration/slb/guide/classlb.html#wp1114235

http://www.cisco.com/en/US/docs/app_ntwk_services/data_center_app_services/ace_appliances/vA3_1_0/configuration/slb/guide/classlb.html#wp1114691

Similarly for RTSP Inspection its clearly stated at

http://www.cisco.com/en/US/docs/interfaces_modules/services_modules/ace/v3.00_A2/configuration/security/guide/appinsp.html#wp1318637

For RTSP inspection

The ACE supports TCP only in conformity with RFC 2326.