Front End pool failed over

Hi all,
1. I setup a pool with three Front End servers (FQDN of pool is pool.site1.sip96x2.com and it's pointed to IP address of three Front End servers). Everything works fine. But When I disable network interface on FE1 and FE2, the Lync clients are disconnected.
I haven't understood clearly how the Lync clients failed over in a pool? Please clarify to me.
2. I have two central site (Root site and Primary site, they have different domain sip96x2.com and site1.sip96x2.com). The simple URL dialin is pointed to Front End server at Root site. So if the link between Root site and Primary site is down, how can the
users at Primary site connect to dialin URL?
3. In building topology for Front End pool, I checked Override FQDN internal web service and the FQDN is "poolint.site1.sip96x2.com". I created three A records "poolint.site1.sip96x2.com" and pointed to three IP addresses of Front End
servers. Is it right?
Thanks so much!

Ah ok, well first thing if I am reading this correctly, pool pairing Standard with Enterprise is not supported. You should only pair Standard with Standard and Enterprise with Enterprise (even though topology builder won't stop you) Take a look here for
support scenarios http://technet.microsoft.com/en-us/library/jj204697.aspx
To deal with the simple URLs in the event of failover you need to add them using Powershell. Take a look at this article which explains and gives an example: http://blogs.perficient.com/microsoft/2012/01/configuring-simple-urls-for-multiple-lync-pools/
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Georg Thomas | Lync MVP
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@georgathomas
Lync Edge Port Check (Beta)

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How Front End pool deals with fail over to keep user state?

   Hello to all, I searched a lot of articles to understand how Lync 2010 keeps user state if a fail happens in a Front Pool node, but didn't find anything clear.
     I found a MS info. about ths topic : " The Front End Servers maintain transient information—such as logged-on state and control information for an IM, Web, or audio/video (A/V) conference—only for the duration of a user’s session.
This configuration
is an advantage because in the event of a Front End Server failure, the clients connected to that server can quickly reconnect to another Front End Server that belongs to the same Front End pool. "
    As I read, the client uses DNS to reconnect to another Front End in the pool. When it reconnects to an available server, does he lose what he/she was doing at Lync client? Can the server that is now hosting his section recover all
"user's session data"? Is positive, how?
   Regards, EEOC.

The presence information and other dynamic user data is stored in the RTCDYN database on the backend SQL database in a 2010 pool:
http://blog.insidelync.com/2011/04/the-lync-server-databases/ If you fail over to another pool member, this pool member has access to the same data.
Ongoing conversations and the like are cached at the workstation.
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SWC Unified Communications

Lync 2013 On Prem - Front End Pool - Second server in pool becomes unavailable when first server is offline

We have one front end pool, that contains 2 front end servers running Lync Server 2013.
When the first server, LFE01 goes offline (to be restarted for instance), the second front end server LFE02 in the same pool's Lync services will suddenly stop and will refuse to start until LFE01's Lync services have started again.
During this time, the Lync client will go from full functioning mode whilst LFE01 is up and running, to reduced functionality (when LFE01 is restarting), to the user being signed out of Lync and not able to log back in. As soon as LFE01 comes back up, users
can log back in to Lync.
We'd ideally like LFE02 to take over the front end server role whilst LFE01 is restarting, and vice-versa.
Checking the event logs on LFE02, I can see the following errors when LFE01 is offline:
This process was not able to update its health status
The Audio-Video Conferencing Server failed to send health notifications to the MCU factory at https://frontendpool.contoso.com:444/liveserver/mcufactory/.
Failure occurrences: 30, since 7/11/2013 3:40:38 PM.
Cause: Either the Front End service is not running, or poor network connectivity.
Resolution:
Verify that the Front End Service is available, and its machine is visible over the network.
This process was not able to update its health status
The IM Conferencing Server failed to send health notifications to the MCU factory at https://frontendpool.contoso.com:444/liveserver/mcufactory/.
Failure occurrences: 30, since 7/11/2013 3:40:42 PM.
Cause: Either the Front End service is not running, or poor network connectivity.
Resolution:
Verify that the Front End Service is available, and its machine is visible over the network.
Server startup is being delayed because fabric pool manager is initializing.
Cause: This is normal when Pool is bootstrapped and indicates that the Front-End is waiting for a quorum of other Front-Ends to be started.
Resolution:
If this event recurs persistently, ensure that 85% of the Front-Ends configured for this Pool are up and running. For 2 or 3 machine Pools, initial cold-start of the Pool requires all machines to be started. If multiple Front-Ends have been recently
decommissioned, run Reset-CsPoolRegistrarState -ResetType QuorumLossRecovery to enable the Pool to recover from Quorum Loss and make progress.
Does the first server in the pool need to be up at all times for the second server to be running? If so, I may need to re-plan my redundancy.

I can't believe how inaccurate these statements are.
Yes as per Microsoft it is best practice to have 3 FE in a pool but that absolutely does not mean that if you have 2 FE server in a pool that your pool will stop working!!
In case when you do have 2 FE servers in a pool your Back End primary database server will act as a vote to keep the quorum for single server still left in a pool and all your clients will keep operating in a pool with one FE still running.
The problem with having 2 FE in a pool as per Microsoft documentation is as follows:
If one of the two Front End Servers goes down, you should try to bring the failed server back up as soon as you can. Similarly, if you need to upgrade one of the two servers, bring it back
online as soon as the upgrade is finished.
If for some reason you need to bring both servers down at the same time, do the following when the downtime for the pool is finished:
The best practice is to restart both Front End Servers at the same time.
If the two servers cannot be restarted at the same time, you should bring them back up in the reverse order of the order they went down.
If you cannot bring them back up in that order, then use the following cmdlet before bringing the pool back up:.
http://technet.microsoft.com/en-us/library/gg412996.aspx
I tested this in my environment which I currently am running with 2 FE servers and I can categorically confirm that pool will continue operating.
However, with all this said I did notice that clients with connection to FE server that is shut down take anywhere from 2-9 min to reconnect. I was trying to figure out why such a long delay until clients reconnect. Possibly it might be because there are
2 FE servers in a pool and Back End server is taking a while to vote in turn delaying auto reconnect process for clients. Second possibility that I'm looking into is that we deployed HLB for sip traffic internally as well and I'm curious if using DNS LB would
fix this delay.
I'm just so disappointed how inaccurate some of these accepted answers above are.

Lync Server 2013 Front End Pool Mediation Service only works on one node

Hello, I'm currently experiencing an interesting issue with a Lync 2013 Front End Pool implementation on a customer, and I don't know if this is by design or am I missing something.
We implemented 3 Enterprise Front End Servers in a Pool with a hardware load balancer and we have them configured also as a mediation Pool.
We have a SIP trunk to an Avaya PBX which was perfectly working before on a Lync 2010 Implementation that we migrated to these new 2013 Front End Pools.
Now the SIP traffic is only working when configured directly to one node of the pool. If we configure it to any other node the calls fail. We also tried configuring the HLB for port 5060 for the pool and pointed the PBX to that IP but the calls also fail.
Searching around I read something about that the PBX has to be Lync certified in order to use DNS load balancing to send SIP traffic to the mediation pool, however, I don't think DNS load balancing will work because the other nodes doesn't connect the calls
from the PBX, only one node appears to be listening for the SIP Trunk.
I also restarted the mediation service on one non-working mediation server node and the event viewer on the working mediation server node showed events that it restarted the service, Not the non-working one, it's like only one server from the pool
is doing as mediation server.
So even if I get a Lync Certified PBX/Media Gateway, the mediation service doesn't appear to be load balanced, or how does it work in order to do that?
Thanks.
Eduardo Rojas

Just a few things about what should be happening. Each front-end server should be listening on the port configured in topology builder for the mediation service. So if that is port 5060, verify that you see that port listening on all front-end servers
by running a netstat -ano. From a local workstation, also make sure you can connect to that port via a telnet IPAddress 5060. As you say, you should be able to send any of the three mediation servers an inbound call.
Outbound calls will round robin out of the enterprise pool. So you shouldn't see all of the calls coming out of a single server.
A few other items I would look into:
- Make sure your ports are right. Ensure that you are matching ports on the Avaya and Lync. It's not a hard requirement but makes life easier to troubleshoot. So if the Avaya is 5060, just make sure TCP/5060 enabled in your mediation pools
and that your gateways/trunks are also set to TCP/5060.
- Look outside the Lync Event Viewer and see if anything strange (.net errors) are being tossed anywhere else during startup of the mediation service. I once had to remove the mediation server installer (Program and Features | Remove) and rebootstrap
the server because something went sideways during an install.
Thanks,
Richard
Richard Brynteson, Lync MVP | http://masteringlync.com | http://lyncvalidator.com

The installation of SAP Front-End components failed with 95 errors.

I tried to install SAP GUI 7.20 on Windows Vista X64. And I got this error message:
The installation of SAP Front-End components failed with 95 errors.
This 7.20 version used to run on this operating system fine. I reinstalled the OS, and now I got this.

Hi,
I suppose you reinstalled the same OS.
Did you install the JSDK (java) afterwards. As you must be aware Java is a pre-requisite for the SAP Frontend.
Also make sure you have set the environment variables after installing java.
Further documentation, the SAP installation manual can be found in the u201CDOCUu201D folder of the installation software.
Regards,
Rohan.

Lync 2013 Edge server compatibility with Lyn 2010 Front end Pool

Hi All,
Technet article (http://technet.microsoft.com/en-us/library/jj688121.aspx) says the following:
If your legacy Lync Server 2010 Edge Server is configured to use the same FQDN for the Access Edge service, Web Conferencing Edge service, and the A/V Edge service, the procedures in this section are not supported. If the
legacy Edge services are configured to use the same FQDN, you must first migrate all your users from Lync Server 2010 to Lync Server 2013, then decommission the Lync Server 2010 Edge Server before enabling federation on the Lync Server 2013 Edge Server.
Can you tell me why it is you have to change the External Lync Web services URL during a migration to Lync 2013 from Lync 2010. What purpose does this serve?
Also can you clarify this and explain why this is required, why would you have to migrate all of your users, would a Lync 2013 Edge not talk to a Lync 2010 front-end?
Any help would be much appreciated. MANY THANKS.

Thank you very much for all your inputs.
We still have few questions:
Questions:
Can you tell me if Lync 2010 users will be able to login using mobility if we repoint the reverse proxy (TMG) web services publishing rule to the Lync 2013 server? Remember both systems Lync 2010 and 2013 are using the same web
services URL so they will both end up at the Lync 2013 server. Alternatively if not we will migrate all users to 2013, this is not a problem
In addition to this I cannot find anything that states how Exchange UM will operate when you are running from a backup pool and the exchange UM contacts are not available because they are homed on the server that is down. This
configuration is 2 x standard edition servers pool paired. How can we make sure Exchange voice mail works during a pool failover?
Call Park is not clear to me I read the following:
Lync Server 2013 provides new disaster recovery mechanisms in the form of failover and failback processes. These failover and failback processes support recovery of Call Park functionality by allowing
users who are homed in the primary pool to leverage the Call Park application of the backup pool when an outage occurs in the primary pool. Support for disaster recovery of the Call Park application is enabled as part of the configuration and deployment of
paired Front End pools.
Is this saying we need to deploy Call Park in the DR pool and use a different range of orbit numbers, or can we use the same range in the DR pool?
Further, I can see that Common Area Phones will be fine as they will log into the DR pool automatically. Response Groups need to be exported and imported to the DR pool. Incidentally these did not migrate well at all and have
caused us a big headache!
Any inputs will be greatly appreciated. Thanks again for all of your time.

Are Registrar pool and Front end pool one and the same?

Hi,
What is the RegistrarPool parameter which is used in Enable-CsUser command?
Is it same as Front end pool because whenever I search for information on Registrar pool, I end up with the links explaining about Front end pools?
Are there any msdn or technet links which talk about this?
Thanks in advance,
Sandeep

Hi Sandeep,
The registrar pool is the pool where user's Lync account is homed.
So if you have a single pool in your Lync environment, then the registrar pool will be same as front end pool. If you have multiple front end pools and you want to find out a user's registrar pool, you can
1. either check the user account in control panel
2. Check the parameter RegistrarPool for a user by running "get-csuser -identity useralias"
Hope this helps.
Regards,

Network ports between Lync front end pools

Dear All,
One of my client have two lync front end pools, at present all the ports are opened between these two pools, now we want to restrict the network ports between the pool servers.
please help me to, which are the ports need to open between different lync front end pools.

There's a bunch of them, take a look at the resources below:
Ports and protocols for internal servers in Lync Server 2013 https://technet.microsoft.com/en-us/library/gg398833(v=ocs.15).aspx
Lync Firewall Rules Viewer http://blogs.technet.com/b/nexthop/archive/2012/07/03/lync-firewall-rules-viewer.aspx
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Georg Thomas | MVP (Skype for Business)
Blog skype4bexpert.com | Twitter
@georgathomas
Lync/Skype for Business Edge Port Check (Beta)
This forum post is my own opinion and does not necessarily reflect the opinion or view of Microsoft, its employees, or other MVPs.

Could you tell me if it would be supported to pair a two node enterprise edition front end pool inc mirror sql with a one node enterprise edition front end pool inc single sql?

Hi all,
Could anyone tell me if it would be supported to pair a two node enterprise edition front end pool inc mirror sql with a one node enterprise edition front end pool inc single sql?
MUCH THANKS.

The answer from TechNet found at http://technet.microsoft.com/en-us/library/jj204697.aspx Is, and I quote:-
Enterprise Edition pools can be paired only with other Enterprise Edition pools. Similarly, Standard Edition pools can be paired only with other Standard Edition pools.
Also, "Neither Topology Builder nor topology validation will prohibit pairing two pools in a way that does not follow
these recommendations. For example, Topology Builder allows you to pair an Enterprise Edition pool with a Standard Edition pool.
However, these types of pairings are not supported."
Please remember, if you see a post that helped you please click "Vote As Helpful" and if it answered your question, please click "Mark As Answer"

Unable to search GAL on Lync 2013 Front End Pool through Lync 2013 client

I'm in the beginning of a 2010 to 2013 migration and I'm currently testing co-existence functionality between pools. I've noticed that users cannot search the GAL from their Lync client after being moved to the 2013 pool.
When trying to access the internal URL https://fepool13.domain.com/abs/handler the user is prompted to login and after three failed attempts, receives "401 - Unauthorized: Access is denied due to invalid credentials. You do not have permission
to view this directory or page using the credentials that you supplied".
Searching withing a Lync 2010 or Lync 2013 client returns no results, but there are no errors as well as nothing in the event logs or tracing folder regarding not being able to search.
The 2010 pool has been in production for a few years now and when accessing its internal ABS URL https://fepool10.domain.com/abs/handler the user is granted access after a successful login.
In the IIS logs there are slightly more detailed 401 error codes, but I’m not sure what to make of them.
The rtcab database appears to have user information and all three front end servers appear to be syncing with active directory. I say the rtcab database appears to have user info because the AbUserEntry table is filled with User ID'd, GUID's and a
bunch of other stuff.
The authentication on 2013 front end servers “internal lync website/abs/handler” is set to 1. Negotiate, 2. Ntlm - which is the same as the 2010 front end servers.
Any ideas?

Hi,
Which step did you do among migration from Lync Server 2010 to Lync Server 2013?
Did you already move CMS from Lync Server 2010 to Lync Server 2013?
Please create a new Lync account on Lync Server 2013 pool and test the issue again.
Please check if User Replication has completed with the help of the link below:
http://technet.microsoft.com/en-us/library/jj204680.aspx
Best Regards,
Eason Huang
Eason Huang
TechNet Community Support

Ports between two front end pools

Hi all,
We plan to build 2 pools in two geographical locations. They are active-active sites, in case of one site failure we would move all the uses from the failed site to the surviving sites.
What are the ports that need to be open between these pools?

Hi,
Lync firewall rule viewer tool may help you ;
http://blogs.technet.com/b/nexthop/archive/2012/07/03/lync-firewall-rules-viewer.aspx
Thanks
Saleesh
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Strange issue with Lync 2013 Front end pool and UC Endpoints.

I have two servers in a Lync Pool.
S1 and S2. I also have an ACD server that has Trusted endpoints within Lync.
With both servers running, if a call is answered by S2 there are a bunch of weird delays in transfers. IF I shut down S2, everything works right. If I just run S2, the endpoints just ring forever and never pick up.
Additionally, with just the S1 server running, in and out calls are fine. With just the S2 server, outbound is delays and no inbound work.
It seems like there is something wrong with the S2 server, but what could it be?
Alex.

Hi,
Agree with Edwin.
Did you receive any error message from FE S2 when the issue happen?
Please double check the network status between FE S2 and ACD Server, on Lync Server Control Panel, check if FE S2 replication status normally.
Best Regards,
Eason Huang
Eason Huang
TechNet Community Support

Front End servers within same Pool on different subnets

The customer is looking to have Amazon AWS host Lync 2013, and despite Lync 2013 having built in HA via Pools, Amazon wants to split the Pools across two of their availability zones (AZ ). An AZ is nothing more than a metropolitan area network, or simply
a data center located a few miles away. Essentially they want to split the Pools between their two AZs.
I know that for Lync 2013, the only stretch Pool supported is the Persistent Chat server Pool, and that Front End Pools, Edge Pools, or Mediation Pools are not supported.
Amazon states that the latency between their AZs is from 1 - 5 ms, which is well within tolerance, though they state that the AZs all have unique subnets.
I know that none of this is supported, though I am being requested as to why it isn't.
Forgetting about latency, is this not supported because all servers within a Pool must share the same IP subnet? Is this coded within Lync that only Pools within the same subnet will work? I think it is as with Lync 2010, a stretched VLAN was required for
a FE Pool to work, which implies the same subnet.
While on this, a Central site does not mirror that of an AD Site, where a Central Site is a reflection of Pools within an area. So can a Central Site span two AD sites? I believe the answer is yes when one considers that a remote branch office can also be
its own AD site. The reason for asking this question is I am attempting to see if if the Central Site might also have something to do as to why stretched Pools aren't supported.
Thanks!
Christian
Christian Frank

Hi Guys,
Just saw both of your responses. I totally agree that it isn't supported, and what Amazon has been proposing is essentially adding their HA via a redundant AZ so that their infrastructure is redundant, which is their HA (I don't agree!).
What I am looking for is something a bit deeper as to why. For example, when Lync 2010 had the stretched FE Pool between two locations, it was done via a stretched VLAN, which implies that the servers on both ends must be on the same subnet.
Amazon wants to stretch all the Pools, between their data centers, so they can say that the Lync infrastructure is highly available, though at each data center, the subnets will be different, and that is what I am attempting to validate.
I know this isn't supported, though is it because the members within the pool would come from different IP subnets, and Lync 2013 is coded to expect fellow members to be within the same subnet? That essentialy is what the case of Lync 2010 FE Pools was when
they stretched them. And if you go back to Exchange 2007, stretched VLAN was back then a way to create geo-clustering also, which is no longer the way.
Frankly, I think it has to do with subnet, and I believe it has to do with how the Windows Fabric is written, and what it is expecting to see. I really think this is the case, which explains the whys as to how stretched Pools are no longer supported any
longer. Yes?
Thanks!
Christian Frank

Lync 2013 Enterprise load balancing on the front end and edge pool

Hi,
I am setting up a Lync 2013 Enterprise deployment consisting of a Front End pool (x2 FE servers) and an Edge pool (x2 Edge servers). I'm seeing some conflicting advice regarding load balancing using hardware or DNS for the front end and the edge.
On the front end I have 2 internal DNS records 'lyncfepool1.contoso.local' each of which map to one of the IPs of the FE servers. I've used my details to populate the Detailed Design Planner excel spreadsheet and am told that I require a HLB to load
balance my front end pool. I'm aware of the need to load balance HTTPS traffic internally (which will be done by TMG) however other traffic to the front end (SIP, etc) can be balanced by DNS only, and not require a HLB?
Can someone clarify the front end requirement?
Also - looking now at the edge pool - this site again have two edge servers in a pool. We are using a total of six private IP addresses, two per edge service (2 x av.contoso.com, 2 x sip.contoso.com and 2 x webcon.contoso.com). These will be
NAT'ed by the external firewall and directed to the respective external (DMZ) IP addresses on the Edge servers on port 443. I know this isn't true roundrobin due to the intelligence of the Lync client when connecting (in that the Lync client will connect
to one of the public IPs and if it can't connect, it will know to connect to the other service IP), however I want to clarify this set up, particularly the need to direct the external public IP traffic at the DMZ Edge IP specified in the topology builder.
I've attached a basic diagram of the external/DMZ/Edge side which hopefully helps with this question
Persevere, Persevere, Per..

That is because you will always need HLB for a front-end server since it hosts the Lync webservices which use HTTP/HTTPS traffic.
The description on the calculation tool also describes this correctly:
Supports Standard and Enterprise pools (up to 12 nodes), with pure device-based load balancing or a combination of DNS load balancing and device-based load balancing (for
Lync web services)
You can use either Hardware or DNS loadbalancing for SIP traffic only, but you will always need a HLB for the webservices. Both are applicable for the Front-End so you have either
full HLB for both SIP and HTTP(S) traffic
DNS LB for SIP traffic and HLB for HTTP(S) traffic
Hope this is more clear :-)
Lync Server MVP | MCITP Lync Server 2010 | If you think my post is the answer to your question, please mark it as answer so future visitors can easily find it.

Front End Server in pool not showing as possible registrar server

Hi All,
We have recently another server to our front end pool. At first we had only one server, and now we have added the second server to the pool.
However doing a get-csuserpoolinfo command we are getting these result
Get-CsUserPoolInfo sip:testuser2@domain
Identity                            :
testuser2@domain
PrimaryPoolFQDN                     : lyncpool.domain
BackupPoolFQDN                      :
UserServicesPoolFQDN                : lyncpool.domain
PrimaryPoolMachinesInPreferredOrder : {fe01.domain}
BackupPoolMachinesInPreferredOrder : {}
PrimaryPoolPrimaryRegistrar         : fe01.domain
PrimaryPoolBackupRegistrars         : {}
PrimaryPoolPrimaryUserService       : fe01.domain
PrimaryPoolBackupUserServices       : {}
BackupPoolPrimaryRegistrar          :
BackupPoolBackupRegistrars          : {}
BackupPoolPrimaryUserService        :
BackupPoolReplicaUserServices       : {}
Now we have fe02 deployed as well however this is not displayed for this testuser or any other user in our deployment. This is also causing the problem that if fe01 is not available the client will not automatically try to connect to fe02.
Thank you for your support!
Joseph

The Replica Instances for Routing Service does not add the second server fe01.domain, however for the other replicas the other server is added.
Get-CsPoolFabricState -PoolFqdn lyncpool.domain
Replica Instances for MCUFactory Service
    Address: fe01.domain - Primary: 6 Secondary: 0
    Address: fe02.domain - Primary: 0 Secondary: 6
Replica Instances for ConferenceDirectory Service
    Address: fe01.domain - Primary: 1 Secondary: 0
    Address: fe02.domain - Primary: 0 Secondary: 1
Replica Instances for Routing Service
    Address: fe01.domain - Primary: 7 Secondary: 0
        Local Groups: Primary: 7 Secondary: 0
        Remote Groups: Primary: 0 Secondary: 0
Replica Instances for LYSS Service
    Address: fe01.domain - Primary: 7 Secondary: 0
    Address: fe02.domain - Primary: 0 Secondary: 7
Global Service Count Summary:
Fqdn: fe01.domain - Primary: 21 Secondary: 0
Fqdn: fe02.domain - Primary: 0 Secondary: 14

Front End pool failed over

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