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Sunday, April 17, 2016
A change of pace
Wednesday, February 17, 2016
Cisco 8841 to Analog Paging Choppy Audio
I know it's been awhile but things have been a bit slow around here so I've been using my spare time to learn Linux inside and out the best I can. Figured another technology under my belt surely can't hurt anything. Last week however was a change of pace with a strange issue.
I have a customer that is experiencing choppy audio when dialing their analog paging system. They are on 10.5(2) so everything in place works and is supported even prior to their upgrade. Their 8841s go off hook and dial a paging number that hits a voice gateway and then pushes out an FXO port to their paging system. Every time they call the number the overhead paging sounds like crap. At first, they thought the paging system was bad but with a buttset hooked up to the POTS line going to the paging system, everything sounded fantastic. That leaves Cisco's side of things.
I had to rule out the DSPs and the FXO port. I had them make a call and after a "show voice call x/x/x" and saw nothing out of the ordinary. Logs on the gateway were also fine so what the heck? They only have a two port FXO card so I wasn't about to ask them to pull their primary line inbound to test. I instead asked a coworker to go on-site and with a spare FXO card that we know works. We swapped out the card and the same thing still happened, so piss!
After that fiasco, we went back to the drawing board and tried dialing from a phone that isn't an 8841 and everything sounded good. That old 7912 from over ten years ago still works and pointed the finger to the 8841. I don't know if it's the G.722 codec, firmware, or somehow and someway SIP is screwing up the call setup using a weird codec but I will need to pull logs to find out for sure. I need to schedule another test call with them and pull logs relevant only to that time period so I can get a fresh cap.
Hopefully this pans out to be firmware but with it suddenly happening who knows. I don't see SIP screwing up since it's just a SIP phone pushing to an H.323 gateway. At that point CUCM should have already done the heavy lifting of protocol conversion.
Monday, January 25, 2016
Out of Compliance on CUCM and need to delete some devices?
Thursday, January 14, 2016
Cisco UCS Password
Thursday, December 17, 2015
Voice PCM capture
- Debug mgcp packet (if applicable)
- Debug isdn q931
- voice hpi capture buffer 1000000
- voice hpi capture destination flash:pcm.dat
- exit
- test voice port 0/0/0:23.23 pcm-dump caplog 7 30
- :::::::::Make Test Call::::::::::::;
- test voice port 0/0/0:23.23 pcm-dump disable
- conf t
- no voice hpi capture buffer 1000000
- no voice hpi capture destination flash:pcm.dat
voice pcm capture buffer 200000
voice pcm capture destination flash:
exit
!
test voice port 0/1/3 pcm-dump caplog 7
:::::::::Make Test Call::::::::::::;
test voice port 0/1/3 pcm-dump disable
conf t
no voice pcm capture buffer 200000
no voice pcm capture destination flash:
On dial peer:
conf t
voice pcm capture buffer 80000000
voice pcm capture destination flash:
dial-peer voice 1
pcm-dump caplog FFFFFFF 254
!
After the all is done, to stop:
conf t
no voice pcm capture buffer 80000000
no voice pcm capture destination flash:
dial-peer voice 1
pcm-dump caplog disable
!
Intermittent one-way audio issues Resolved!
Tuesday, December 15, 2015
Intermittent One-Way Audio on Select phones
At this point I am thinking PRI. I push the call out another PRI and the phones are fine. This nixes the phones being bad as they worked immediately after switching from one PRI to another. This goes back to the PRI being part of the problem but I can see packets being transmitted and received at the proper G.711u-law codec. Ultimately, I am going to have to see if the carrier is willing to troubleshoot since the problem is most likely something sporadic on their side. This problem has been a hindrance since before a major upgrade and followed it afterwards. It is strange for something like this to be popping up like this. More information will follow as I find out the issue.
Tuesday, December 1, 2015
Time between posts
I just wanted to put a post up showing I am still actively here but just haven't had any good content to put up that would be worth reading. I do have a pending outbound call issue that could potentially be useful once I resolve the issue but the ticket hasn't landed yet so I don't know what all is involved.
For what it's worth, the Cisco PEC GoldLabs for UC/Collab are actually fairly well designed. It's clear some of the labs were built around physically being on site but you can do all of them remotely via RDP. There are some errors here and there in the workbooks but nothing that causes issues with following along with the exception of a VoH/MediaSense portion that wanted me to configure an EX90 that the lab left out completely. Even with auto-registration on, you need to be able to access the EX90 and it's IP address is completely left out of the documentation. The image they show that auto-registered isn't accurate as I tried that IP and got nothing.
Tuesday, November 17, 2015
ESXi and NIC Teaming gone wrong
Without being to in detail on ESXi, since I'm no guru, I took a look at the network side of the house and everything looked like it was in working order as well. Pings to and from the ESXi were working but for some strange reason on VM was sending data out one NIC and receiving it on the other. This was the only VM doing this and I think if LACP was enabled it would never have happened. The end result was a VM that wasn't talking correctly and couldn't communicate with it's subscriber. We ended up moving one of the NICs from active to standby and ran a test. Everything magically worked itself out as all traffic was being forced over one lane. We then put it back into active mode and everything still was working fine. Weird.... How did the TCP/UDP data streams end up getting hosed up?
I checked again today and traffic was still evenly distributed and no weirdness was going on behind the scenes with one VM sending out one port and receiving on the other. I'm not sure this was ever a problem as again, I'm not an ESXi expert but it seemed to have resolved the issues and they haven't returned. This also seemed to have fixed a second issue they were getting which was calls going to voicemail but then terminating after 5 seconds. If this was indeed the resolution, nothing was being shown as wrong anywhere on the network and no errors were being thrown. Just a heads up for any of you that run into this issue yourselves. Just bounce the port or go standby then back to active, it should end with the same result.
Friday, November 13, 2015
7940 / 7960 DST change and CUCM 6.x - 7.x
The weird part about all of this is that I changed it earlier this year to bump it ahead an hour and I didn't have to change it again afterwards. I cycled the time back to -7 time since I am on central time and everything was fine. Later last week I got a call that their phones had once again went forward an hour. This didn't make sense at all. I went in and did a screen cap of the 7940 and sure enough, it was showing eastern time again. I set the date/time group back to central time and this ultimately resolved the issue.
So the lesson learned is:
- Upgrade your CUCM
- Get rid of those ancient phones
- Upgrade and get rid of the phones
- Wait a week for the time to change
- Update the CUCM with a COP file
Wednesday, November 11, 2015
T1s being T1s
This was the last 24 hours of my work life. Everything looked good, no errors, no issues except randomly failing calls out a particular site. Sure, I could have re-routed the entire site out another gateway but that would have taken significant time, even with BAT changing out the CSS to route out the other direction. That would also put a huge load on the other T1 bundle and soak up a crap ton of ports and DSPs.
So I sat there, in discontent wondering what was going on. Logs looked good, traces were fairly clean and still Cause Code 41. I tried rapid long distance dialing and got a few calls to work. My thoughts immediately went back to the carrier. I even tried changing out the gateways but since both T1 CASs were failing that was also doomed to fail. I was talking with another voice guy and he figured we should try to reset the T1 CAS. I thought..why didn't I try this? So simple... My thought process was that it was broken however, and now I know better. Reset it even if it is appearing to be working, who cares since long distance isn't working anyways right? I reset the port made about 10 calls and had the customer call me back and everything is hunky doory.
So what was the problem? Damned if I know. Neither of us did anything and the carrier sure didn't do anything. A reset seemed to fix an invisible hangup on the T1. Note to self, just reset the damn T1, even if it doesn't look like it needs it! Also, who the heck still uses T1 CAS? That's the first time I saw a CAS in about 8 years.
Tuesday, November 3, 2015
Unity Connection integration with an analog PBX system
After poking around a bit I found they have a DMG or Digital Media Gateway. This had routes to Unity Connection but was listed second in the top down list. The first thing to fix was this and get rid of the Unity route completely. The issue is, being unfamiliar with the DMG, I was rolling the dice. The configuration menus were not too difficult to figure out but I still didn't full understand everything. It turns out however, my solution was correct.
The next stop was to make PIMG ports on the Unity Connection box. This will allow the analog phones to get their MWI and access their voicemail on demand when pressed. Now the only thing I still don't fully understand in the first place is how the Unity Connection was being used by the DMG as voicemails were being delivered there somehow without the PIMG ports. My guess is that it hit a route elsewhere when it got sent to the Cisco side. However, being on a time schedule to getting something fixed since it was paid per hour, I didn't have too much time to try to figure that aspect out.
Friday, October 23, 2015
CCNA Lab #3
UPDATE: I made a boo boo and Oklahoma should be 192.168.3.0 /26 and 192.168.3.64 /26.
Monday, October 19, 2015
A revisit on SIP
I think one of the biggest issues with SIP is the pure amount of messages that are sent for every transaction. Every time you setup a call you get an INVITE, every time you go on hold, INVITES are sent with certain SDP characteristics announcing a hold status so the call doesn't get torn down. Every time something registers you get a REGISTER message. Basically, everything is recorded down on what is going on.
Below is a basic SIP header from an INVITE, we will go over each header field that is relevant and annotate which ones are mandatory. The thing is with SIP, you are required to have certain SIP headers regardless of what is going on. While others may be optional, headers like To:, From:, Via:, Call-ID:, etc. are all necessary components to the SIP protocol.
SIP/2.0 180 Ringing
Via: SIP/2.0/UDP 182.168.250.49:5060;branch=z9hG4bK786d156c;rport=5060
Contact: <sip:9011@182.168.246.213:35134;rinstance=7af05ded7e7e49e6>
To: <sip:9011@182.168.246.213:35134;rinstance=7af05ded7e7e49e6>;tag=9a00d038
From: "9012"<sip:9012@182.168.250.49>;tag=as66995cd4
Call-ID: 7cebe5d1060b11452571a22e0e2cb919@192.168.250.49
CSeq: 102 INVITE
User-Agent: X-Lite release 1002tx stamp 29712
Content-Length: 0
Now I wish I had a way of generating some SIP traffic right now but I don't have access to a test lab for SIP at the moment since my demo license expired and I'm not in the habit of using a production network for labbing and testing unless absolutely necessary. Anyways, as you can see, the above message is a response as it starts with a number and generally is not capitalized. You still see all the same basic headers here only without the SDP. Please note these are SIP messages I have used from the web and I have changed some of the information intentionally just in case there is a confidentiality issue.- a=sendrecv
- a=sendonly
- a=recvonly
- a=inactive
Friday, October 16, 2015
GNS3 CCNA R/S Lab #2
Please note that this lab may require in excess of 3-5 GB of RAM. My laptop has 8 GB and I was sitting right around 5.16 GB of RAM chewed up from this lab. I'm not taking into account all of my other programs open however, I had email, a ticketing system, and notepad++ open. For Jim's network, it is up to you to design a proper subnet for the GLBP and WAN links. Part of learning is doing something yourself! Whip up a DHCP server while you are at it for him too. IPv6 lab will be coming soon.
- ensure the line console doesn't interrupt your typing
- setup telnet and ssh except Salado-Exec, ssh should only be enabled for this gateway
- configure both the console and vty lines for a password of cisco and enforce logging in
- create a username of cisco and a secret password of cisco
- create a secret enable password of cisco
- make sure random words don't force DNS lookups if you make a mistake typing
- configure all ip interfaces as shown
- configure EIGRP in AS 1 and only send hello packets on interfaces that you own or networks that are completely behind the GW you are on
- Configure the frame relay interfaces according to the DLCI chart
- Configure the frame relay switch
- EIGRP should be establishing adjacencies at this point, verify by pinging across
- configure DHCP for 10.x.x.x networks and exclude .1 to .9 while setting DNS to 8.8.8.8 and the default-router to the .1 address
- make sure all clients get their respective DHCP addresses and other information such as gateway and dns
- configure NAT for the additional router added into the Salado portion to use PAT, ensure nat translations are occuring on the inside global address to the inside local
- configure GLBP for Jim's setup and ensure the timers are set to miliseconds of 50 and 160 dead
- configure static routes for Jim's network to Salado-Exec and beyond
- configure default routes that all point to Corp-HQ in case a route is not known
- configure a proper route in the correct gateways to ensure data gets routed statically to Jim's computer since he is a loner and no one likes him
- configure eigrp md5 authentication between corp HQ and all other cores
- configure PPP Chap between Jim's GWs
- deny telnet to all gateways except from the engineers and IT networks
- deny ssh to all gateways except from the engineers and IT networks
- ONLY deny the CEO and CFO, permit the CTO to do his job with all engineering tasks like icmp, telnet,ssh
- deny ICMP on all host networks except IT and engineering
- deny http traffic from the corp sales department, they are committing shenangians on youtube
Wednesday, October 14, 2015
A CCNA Lab for those that need extra practice
At a minimum, here is what you need to configure:
- Connect all devices as shown
- Configure all ports with approrpriate addresses and bring them online
- Configure ssh access only with a password of cisco
- Configure a username of cisco and secret of cisco
- Configure an enable secret of cisco
- Ensure that the routers will not mistaken letters for DNS names
- Disable enable timeouts
- Set hosts with IPs so you can use their names instead of IP addresses
- Configure EIGRP and advertise networks based on subnet with no automatic summarization, do not configure Canada nor advertise its networks!
- Exclude the first 10 addresses in all ranges in the private networks for DHCP
- Configure DHCP for all Offices with a /24 subnet based on the network assigned
- Assign default routes to point to the local primary gateway of each site (not the office GWs)
- Ensure all PCs get their DHCP addresses assigned to them and they can ping to their local GW
- Configure the Frame Relay DLCIs as shown and map them as indicated
- The FR-Switch should not have any other configuration as it is acting like a cloud
- Assign static routes to get to Canada based on location (Texas will be a end all be all GW if other primary gateways don't know the correct path
- Configure NAT for Canada to use the internet IP with PAT
- Ensure all devices can ping to the private network in Canada
- Ensure Canada can ping from internal to any CORP based internal IP (i.e. 10.0.3.11, 10.0.0.1)
- Configure EIGRP md5 authentication for all links
- Make sure that any loopback interfaces assigned are being seen as their subnet in the routing tables
- Block all telnet traffic from all locations except Texas
- Block all SSH traffic on private LANs on all sites except Texas
- Verify NAT on the Canada GW
- Enable password encrpytion globally so that any plain text passwords are garbled at minimum security.