Imaging Causes Phone Problems.

[matthewk2010]

Sorry about the blank submission. I am new to FOG and to the forum, so please forgive any noob mistakes I am bound to make.

FOG Version: 1.3.4
SVN Revision: 6064
OS: Ubuntu 16.10

Network info:
Fog Server is on VLAN 2
The PCs I have tried to image are on VLAN4

I have recently setup a FOG Server, which went pretty smoothly. The trouble started when I tried to deploy an image to one of the clients. When every the imaging process is running it cause our VoIP phone system to cut in and out. The connection is never dropped, but it makes for a very choppy conversation. I have tried deploying different images and both cause the same problem. I think what is occurring is that the multicast is flooding the VLAN, which in turn causes my phone issue. I found this on the forum -> https://forums.fogproject.org/topic/332/multicast-session-flooding-vlan
I check our layer 3 switch and ip igmp snooping had been disabled, so I enabled it and the cutting out is noticeably better but no gone completely. This post also led me to this -> https://wiki.fogproject.org/wiki/index.php?title=Cisco_Multi_Cast
I am only slightly familiar with CISCO IOS, so this is a bit over my head. I can follow the commands, but my issue is that my network has over 2000 devices and I cannot enter these commands for every PC on every VLAN.

Any help would be appreciated!

[matthewk2010]

@Jaymes-Driver

Sorry about the blank post.

They are on their own VLAN. I am not sure if it matters, but in the DHCP Scope options the scope for the phone VLAN is using option 150 to point to the tftp server where the config files are stored and the other scopes are using option 66 and 67 to point the PCs to the FOG server.

[george1421]

@matthewk2010 Are you deploying to the targets using multicast or unicast imaging?

Are your voip phones on the same subnet as your target computers?

What are you using as a router between the vlans?

Is your PBX on the same vlan as your phones?

[Jaymes Driver]

@matthewk2010

Is the tftp server that the VOIP system uses in the same subnet and vlan as the FOG server?

What switches do you use?

This leads me to believe that something in the network, or switches is not configured correctly.

[matthewk2010]

@Jaymes-Driver

No the TFTP server for the phone system is not on the same VLAN as the the FOG server.

Our network is made up of mostly Cisco 2960s running a mix of IOS 15.0 (2) SE10 and IOS 12.2 (55) SE5. Our only layer 3 switch is a 3750X IOS 12.2 (58) SE2.

We used to outsource all of our switch management, but recently downsized that contract so they only manage a few of the core switches. I have access to all of them, but I am not sure exactly what to look for.

[george1421]

@matthewk2010 Are you doing multicast image deployment or unicast? And about how many total devices do you have on your campus that is connected to your network?

[matthewk2010]

@george1421

I believe I am using multicast. I only see multicast settings when I am looking at the FOG Configurations and to my knowledge I have not enabled unicast. Is multicast the default?

No the phones are on a separate subnet all their own.

We are using a CISCO 3750X IOS 12.2(58) SE2

No our PBX is located at our ISPs location.

[george1421]

@matthewk2010 Ok so you have a hosted PBX.

The unicast / multicast thing… You have to specifically do a multicast deployment. This is where you would deploy to 1 or more machines at the same exact time. You have to specifically setup a multicast session. If you don’t specifically know you are doing this, or just picking imaging then you are doing a unicast imaging.

[matthewk2010]

@george1421

I believe I am using multicast. I only see multicast settings when I am looking at the FOG Configurations and to my knowledge I have not enabled unicast. Is multicast the default?

We have around 4000 devices that are connected the network, but only 1500 of those would need access to the FOG Server.

[george1421]

@matthewk2010 OK still driving towards a multicasting answer here.

How to you image a computer? Do you pxe boot the computer, go into the fog menu and select register and image?

Do you schedule an imaging task on the FOG server then pxe boot the target computer and it images right away?

Its probably not relevant but I want to put half of the issues out of my mind when considering this issue.

[matthewk2010]

@george1421

I appreciate your help so ask anything you need to.

Basically all I do is manually boot the PC to the PXE Menu and select deploy image. I select the image I want and then it starts. I have only done this one PC at a time.

[george1421]

@matthewk2010 OK good, you are doing a unicast image deployment.

OK now lets focus on the device that connects your vlans? What are you using as your router? Does that router also interface with your ISP connection to your office PBX?

[Jaymes Driver]

@matthewk2010 This is unicast.

Multicast is when you send the same image to multiple computers at the same time as a “group” task.

They often wait in a Queue and download the same information at the same time. (they will all wait at 30% until all clients are are 30% and then proceed).

[matthewk2010]

@george1421

We are using a layer 3 CISCO 3750X IOS 12.2(58) SE2 for routing and yes it is our connection to our ISP.

[george1421]

@matthewk2010 My bet is that the unicast imaging is flooding your router (between the vlans) and that is causing your audio issues.

Do you have QoS setup on your router (not the ISP router) but the router between the vlans? What we need to have happen is the vlan router needs to put the RTP (audio) part of the voip call ahead of all other traffic.

[Jaymes Driver]

@george1421 Ahh yes, lovely QoS

[george1421]

@george1421 We can test this theory out of you can move a target computer to the same vlan as the FOG server, but have it physically located where your other target computers are.

What I’m getting at is to have the target computer and FOG server on the same vlan then image. See if that causes your VoIP issues. If it doesn’t then we can focus on your router. My guess it will image fine without any voip issues.

[matthewk2010]

Okay I will give that a try tomorrow and see what happens.

Here are the QOS settings that are currently on the routing switch.

mls qos map cos-dscp 0 8 16 24 32 46 48 56
mls qos srr-queue input bandwidth 70 30
mls qos srr-queue input threshold 1 80 90
mls qos srr-queue input priority-queue 2 bandwidth 30
mls qos srr-queue input cos-map queue 1 threshold 2 3
mls qos srr-queue input cos-map queue 1 threshold 3 6 7
mls qos srr-queue input cos-map queue 2 threshold 1 4
mls qos srr-queue input dscp-map queue 1 threshold 2 24
mls qos srr-queue input dscp-map queue 1 threshold 3 48 49 50 51 52 53 54 55
mls qos srr-queue input dscp-map queue 1 threshold 3 56 57 58 59 60 61 62 63
mls qos srr-queue input dscp-map queue 2 threshold 3 32 33 40 41 42 43 44 45
mls qos srr-queue input dscp-map queue 2 threshold 3 46 47
mls qos srr-queue output cos-map queue 1 threshold 3 4 5
mls qos srr-queue output cos-map queue 2 threshold 1 2
mls qos srr-queue output cos-map queue 2 threshold 2 3
mls qos srr-queue output cos-map queue 2 threshold 3 6 7
mls qos srr-queue output cos-map queue 3 threshold 3 0
mls qos srr-queue output cos-map queue 4 threshold 3 1
mls qos srr-queue output dscp-map queue 1 threshold 3 32 33 40 41 42 43 44 45
mls qos srr-queue output dscp-map queue 1 threshold 3 46 47
mls qos srr-queue output dscp-map queue 2 threshold 1 16 17 18 19 20 21 22 23
mls qos srr-queue output dscp-map queue 2 threshold 1 26 27 28 29 30 31 34 35
mls qos srr-queue output dscp-map queue 2 threshold 1 36 37 38 39
mls qos srr-queue output dscp-map queue 2 threshold 2 24
mls qos srr-queue output dscp-map queue 2 threshold 3 48 49 50 51 52 53 54 55
mls qos srr-queue output dscp-map queue 2 threshold 3 56 57 58 59 60 61 62 63
mls qos srr-queue output dscp-map queue 3 threshold 3 0 1 2 3 4 5 6 7
mls qos srr-queue output dscp-map queue 4 threshold 1 8 9 11 13 15
mls qos srr-queue output dscp-map queue 4 threshold 2 10 12 14
mls qos queue-set output 1 threshold 1 100 100 50 200
mls qos queue-set output 1 threshold 2 125 125 100 400
mls qos queue-set output 1 threshold 3 100 100 100 400
mls qos queue-set output 1 threshold 4 60 150 50 200
mls qos queue-set output 1 buffers 15 25 40 20
mls qos

[george1421]

@matthewk2010 well I’m not a cisco freek so it will take me until tomorrow to decode this. I am a very old network engineer so I understand the bits and bytes of the issue.

The other thing is that you need to ensure your phones are tagging their traffic with using dscp (according to what you just posted).

[Wayne Workman]

@Jaymes-Driver said in Imaging Causes Phone Problems.:

Ahh yes, lovely QoS

Crap QoS. IPv4 itself is flawed. A large transfer doesn’t allow other packets through, it’s like a missile going down the wire. There’s been an integration recently into the Linux Kernel called fq_codl that solves this issue, it was authored by Dave Taht. If you used routers and switches that run using a new linux kernel, you can blast the network as heavy as you want to with as many streams as you want to, as many massive file transfers and imaging as you want to - with no configured QoS - and no seperation of services via VLans - and VoIP will be crystal clear - because the kernel will make room for the smaller packets to go through no matter what.

If you need QoS, then really you need a new network.

</rant>