VCS Expressway Cluster DNS SRV Records

[joemartinez316]

Hello Support,

I've seen many examples of the DNS SRV records and have read the  VCS Cluster Creation Deployment Guide for X8.1 example. I was hoping I could a second set of eyes to verify that my DNS configuration below is accurate. Here is what I have so far:

VCS Expressway LAN 1 Ports are to be used for the VCS Cluster in the DMZ and will not be NAT'd. LAN 2 Ports point to the public internet and are NAT'd.

- Domain: vc.example.com

- Cluster A Record: vcse-nb.vc.example.com points to both VCS Expressway IP address in Round Robin fashion with equal weight and priority (12.x.x.1 and 12.x.x.2)

- VCS Expressway A Records

Vcse-nb-1.vc.example.com – 12.x.x.1

Vcse-nb-2.vc.example.com – 12.x.x.2

DNS SRV Records

_sips._tcp.vc.example.com. 86400 IN SRV 1 1 5061 vcse-nb-1.vc.example.com.

_sips._tcp.vc.example.com. 86400 IN SRV 1 1 5061 vcse-nb-2.vc.example.com.

_sip._tcp.vc.example.com. 86400 IN SRV 1 1 5060 vcse-nb-1.vc.example.com.

_sip._tcp.vc.example.com. 86400 IN SRV 1 1 5060 vcse-nb-2.vc.example.com.

_h323ls._udp.vc.example.com. 86400 IN SRV 1 1 1719 vcse-nb-1.vc.example.com.

_h323ls._udp.vc.example.com. 86400 IN SRV 1 1 1719 vcse-nb-2.vc.example.com.

_h323cs._tcp.vc.example.com. 86400 IN SRV 1 1 1720 vcse-nb-1.vc.example.com.

_h323cs._tcp.vc.example.com. 86400 IN SRV 1 1 1720 vcse-nb-2.vc.example.com.

My question is in this example would I need to create SRV records that point to the Cluster A record? I have seen many examples of this but I can't seem to wrap my head around why this would be needed. I appreciate you help!

Thanks,

Joe

[tec cou]

Yes !! but did not know the concepts, domain, a record, round robin, was not able to order the information for transmission to the board administrator dns.

dns this is confusing to me.

last question, without dns, failover will not work, it really is DNS who does.

thanks

[Patrick Sparkman]

I understand, I was the same way at first.  The SRV records is what provides the failover from one server to another, you can change their priority and weight to do this.

H323 endpoints when registering to a VCS cluster will be sent a list of alternate gatekeepers, the other peers in the cluster, and will try each one in case the VCS it's registered to fails.  SIP endpoints you can configure multiple registrars in the endpoints configuration, and it will try each in case of a failure.

[alpepate]

For your Option #2 "Create H323/SIP SRV records and point them to a single VCS Expressway cluster FQDN", you mentioned the downside is you can't prioritize one peer over another and thus require DNS round-robin to manage this.  I'm confused.  Wouldn't the priority and weight specifications in the DNS SRV actually handle prioritization of one peer over another without the need for DNS round-robin?