09-21-2022 03:49 AM
Hi All,
I could do with some advice regarding transitioning from H323 endpoint registration to SIP on Cisco Expressway cluster. Yes appreciate this has taken time!
What I'm struggling with is the documentation recommends two options for SIP registration as my endpoint are running the latest CE SW.
- DNS SRV
- DNS Round Robin
My issue is I'm struggling to find any documentation with recommendations and examples of how to configure this. What I'd like to achieve is to be registered to the primary expressway in a two peer cluster - Active/Passive.
Could anyone kindly offer some pointers, not including migrate to CUCM.
Kind regards,
Rob
09-21-2022 08:28 AM
Nothing I’ve done myself, but given how DNS SRV records works I would think that you’d be using that for your requirements. Create two SRV records with different values for weight and/or priority, if your unsure on how this operates please read up on the topic, so that endpoints uses the primary Expressway as the preferred registrar and the second if there is no response from the first.
09-21-2022 11:24 AM
Hi Rob,
In SIP device settings of your EndPoints you can use several SIP Proxy and use your two Expressways.
EndPoint will always register on first SIP Proxy, and use second in case only if it has failure connection to first Expressway.
BR Oleksandr
09-22-2022 11:51 AM
Hi Oleksandr,
Thanks for the response, unfortunately this feature was deprecated on the endpoint from CE version 8.0.
Kind regards,
Rob
09-21-2022 09:44 PM
@Rob_Passey Please see my notes below. This is my understanding of how they work. I hope this helps.
1. DNS SRV method (Not all device types are supported)
Below are some sample SRV records under DNS Domain=example.com
Internal DNS SRV Records using TCP (For non-secure registration)
Service: _sip Protocol: _tcp Priority: 5 Weight:10 port: 5060 Server: expresswayC1.company.com
Service: _sip Protocol: _tcp Priority: 10 Weight:10 port: 5060 Server: expresswayC2.company.com
Public DNS SRV Records using TLS (For secure registration. This is needed if you register devices over internet)
Service: _sips Protocol: _tls Priority: 5 Weight:10 port: 5061 Server: expresswayE1.company.com
Service: _sips Protocol: _tls Priority: 10 Weight:10 port: 5061 Server: expresswayE2.company.com
Now, let's say you are trying to register a video endpoint at extension 1000 over TCP. In the SIP URI field of the device, you enter 1000@example.com, and set the protocol to TCP. The SIP device sends a "_sip._tcp.example.com" request to IP Address of it's configured DNS server. The DNS server comes back with the FQDN, Protocol type and the port number of an expressway C server
,in this example, expresswayE1.company.com. Then the device will send a registration request to this server. If the endpoint is on the internet, and you set the protocol to TLS, _sips._tls.example.com record is used and the device will register via the expressway E over TLS. Obviously, TLS can be used for local registrations as well if the internal SRV records are configured. Also, You can use the Priority and Weight values to control the distribution algorithm which is the benefit that comes with this method. In the example above, the devices always register to the primary node first, and use the secondary for failover, but if you set the weight to 7 on the first SRV record, and 3 on the second SRV record, then set priority to 10 on both SRV records, 70 percent of devices will register to the Primary node, and 30 percent to the secondary node.
2. DNS Round Robbin Method.
In this method, you use the FQDN of the Expressway cluster in the Proxy 1 address field of the endpoint. This way, the device will have access to all the Expressway server nodes in the cluster, and if one goes down, the device fails over to the next available node. You cannot control what devices register to which node since the registration requests are distributed in a Round Robbin fashion.
3. Using Static Addresses
You enter the IP Address or FQDN of the primary Expressway in the Proxy 1 Address field, and enter the IP address or FQDN of the secondary Expressway in the Proxy 2 Address field. Devices will always register to Proxy 1 Server, and use Proxy 2 Server for failover. Here you, you have the same level of control as the DNS SRV method but you need to enter the addresses manually.
09-22-2022 11:47 AM
Hi TechLvr,
Many thanks for your response, I should have mentioned I'm happy with the DNS SRV config as I've used it for pointing calls to expressway, I was just unsure how this would register the devices to expressway, and how to configure the endpoints.
So just so I'm clear, you don't configure a SIP Proxy on the endpoint, just add the URI and it should send a DNS request which the DNS SRV will respond, and point the registration request to the Expressway hostname? I hope I've explained this clearly.
I've configured the DNS RR method this works well, but I can't control the Expressway which is why I'd prefer the SRV method.
The static IP method is now deprecated in the version of CE I'm currently running on the endpoints.
Kind regards,
Rob
09-22-2022 12:11 PM
@Rob_Passey That's correct. "you don't configure a SIP Proxy on the endpoint, just add the URI and it should send a DNS request which the DNS SRV will respond" back with the FQDN of an Expressway node to register with.
Interesting. I was not aware of the deprecation of the static method.
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