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New Member

VCS Expressway Cluster DNS SRV Records

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

 

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16 REPLIES
VIP Purple

There are a few ways you can

There are a few ways you can approach this.

  1. Create an SRV record pointing to each VCS peer A record.  This would lead to two SRV records for each protocol pointing to the different VCS peers.
  2. Create an SRV record pointing to a cluster FQDN, which in turn is pointing to the different VCS peers.  This would lead to a single SRV record for each protocol pointing to the FQDN of the VCS cluster.

I've seen some sites that use either methods above, and they both work.

Going off of your examples in your post, you are correct.

New Member

Thank you Patrick! So in my

Thank you Patrick! So in my scenario would the Cluster A record just be used for endpoint registration and redundancy while the DNS SRV records would be used for locating the VCS Expressways based upon the service protocol for call processing?

VIP Purple

I've never really understood

I've never really understood the part about the cluster FQDN portion of the deployment guide, I believe it was used with the old provisioning model within TMS, (TMS Agent Legacy), but I can't say for certain.

DNS SRV records could be for both registration and calling.  Note, if you'd like to use SRV records to register H323 endpoints, you'd also need to include _h323rs._tcp over port 1719.

We use a single SRV record for each protocol/port pointing to a cluster FQDN, which has each peers A record assigned to it.  If anything, you could configure all parts of it if you're unsure.  I know I ran through this same scenario as you when we implemented a VCS Expressway this past December, trying to wrap our heads around the DNS portion, what is what, and how to best approach it.

New Member

Hi Patrik, I have many doubts

Hi Patrik, I have many doubts or round robin dns srv , but your explanation is very good.

as in the previous example :

We use a single SRV record for each protocol/port pointing to a cluster FQDN, which has each peers A record assigned

How to do that in DNS?

name = 1 ip?

Sorry , I do not know dns

thans

 

VIP Purple

Alejandro -SRV record would

Alejandro -

SRV record would point to your VCS Expressway cluster FQDN.  Your VCS-E cluster FQDN would point to each Expressway peer.  You create an A record with the same domain entry for each peer IP address.

New Member

then :A record for each vcse

then :

A record for each vcse :

vcse1.vc.domain.com point IP public vcse1

vcsex.vc.domain.com point IP public vcsex

FQDN for cluster name :

 

vc.domain.com point to vcse1.vc.domain.com and vcsex.vc.domain.com?

 

oh , sorry , my knowledge are very limits !!!

 

 

 

 

 

 

 

VIP Purple

vc.domain.com points to both

vc.domain.com points to both vcse1 and vcsex IP address.  In DNS, you can create an A record using the same domain (vc.domain.com) pointing to several IPs.  And anything trying to communicate to that domain will use round-robin, making their way through each IP.

New Member

oh ! i`m Sorry I do not

oh ! i`m Sorry I do not understand.
I'll make a diagram to put it graphically.

 

New Member

attach simple diagram ,

attach simple diagram , thanks 

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