CVoice Chapter 1 Notes

For anyone reading/studying for Cisco’s CVoice exam, here are my notes from the exam cert guide chapter 1. WordPress kind of jacks with the formatting and I don’t feel like going back and correcting it. If you’d like a PDF version, then go here, fellow voice lover.

Chapter 1

• Signaling protocols generate control traffic/information between 2 endpoints
  • Peer to Peer
  • Client-Server
• Peer to Peer Signaling Protocols
  • H.323 – Umbrella of standards for voice, video, and data transmission
    • Includes the following protocols
      • H.225 Call signaling – establish a connection between 2 H.323 endpoints or and endpoint and a gateway
      • H.225 Registration, Admission, and Status – provides registration, admission, status, bandwidth changes, and disengage procedural messages between endpoints and gatekeepers
      • H.245 control signaling – provides end to end control messages about capabilities, opening/closing logical channels, flow control, general commands
  • SIP – Similar to http with URLs and status codes
    • Works with SAP (session announcement protocol) and SDP (session description protocol)
    • H.323 alternative
    • UAs (user agents) initiate sessions
    • SIP devices do not register with a call manager
• Client-Server Signaling Protocols
  • MGCP – protocol for PSTN gateway control
    • Controls VOIP gateways that are connected to call agents
    • Provides signaling for edge devices that do not have a full voice signaling protocol
    • All dial plan info resides on a separate call agent (not the CM)
    • Plain text protocol
    • Call manager knows of and controls individual voice ports on an MGCP gateway
  • SCCP – TCP skinny client control protocol between call manager and client
    • Cisco proprietary
    • Used between call managers and endpoints
    • All events cause traffic to the CM (the CM will tell the endpoint what to do in response to that event)
• Media Transmission Protocols
  • RTP – real time protocol
    • Communicates directly between endpoints
    • Uses multiplexing and checksum offered by UDP
    • Communicates on an even port, vs RTCP communicating on an odd port
  • RTCP – real time control protocol
    • Provides control info for RTP
    • Primary function is to provide feedback on the quality of service provided by RTP
      • Monitors traffic sent, jitter, feedback, delay and can signal the device to use higher compression codec if needed
  • cRTP – compressed RTP
    • RTP header is generally larger than the data it carries (40 byte header! – 20 IP bytes, 8 UDP, 12 RTP
    • Header compression results in 2-4 byte headers (the endpoints actually cache the header info and don’t necessarily compress it)
    • Useful on WAN links
  • sRTP – Secure RTP
    • Provides encryption, message authentication, integrity, and replay protection
    • sRTCP also
    • Uses AES encryption only
    • Uses HMAC-SHA1 for integrity and authentication – calculated for entire IP packet
• VOIP Gateways – connects VOIP systems to PSTN, PBX, or other TDM systems
  • Analog gateways provide connectivity from IPT to POTS or connect fax machines, etc. to VOIP systems
  • Analog trunks connect IPT to PSTN or PBX using FXO ports and E&M ports to connect to legacy PBX’s
  • Digital gateways connect IPT to PBX or PSTN using digital (PRI/BRI) trunks

Upgrading Cisco IP Phone Firmware for CUCME Simplified

So as I mentioned, I’ve recently gotten into the voice realm at work. For the past few days, I’ve been installing and configuring CUCME and CUE on a 2901 router for a small satellite office. For someone who’s never worked with this technology before, it was admittedly a bit overwhelming at first. I get the general idea of what is supposed to happen, but actually making it happen has been a different story.

One problem I ran into is that the 7942 phones we had were displaying the wrong time. After verifying that all of the time zone and clock settings on the router and the ISM were correct, I was lost. I then ran across this link on Cisco’s website. Simple enough…seems like the firmware could affect the time being displayed on the phone. Weird, but ok.

So I begin on the mission learning how to upgrade the firmware. I like to think that I am relatively competent. I will however, sometimes glance over small details that can make a lot of difference. After finally ending up here, (from here — probably the more important link), I found the firmware files, but couldn’t figure out which load file to use. Therein lies the details…

If you look at the section labeled “Important Information about Configuring Cisco Unified IP Phone Support” – it tells you to “configure only the filenames that are marked with an asterisk (*) in the table below.” HA! Well, that was an important fact…the one that I glanced over probably 5 times and didn’t register for some reason.

Anyhow, the simplified version (which is presumably what you ended up here for) is this:

1. Find your CUCME version at this link
2. Find your phone(s) model (and protocol) in the first table shown (Cisco Unified IP Phone Support) – take note of which file has the asterisk next to it
3. Download the firmware files from this link (CCO Login Required – Click Voice and Unified Communications, then IP Telephony, then IP Phones, and then select your model,  protocol, and which firmware version you want to use.
4. Download the zip file to your computer – in my case it was the cmterm-7942_7962-sccp.8-5-4.zip file
5. Extract the files, and upload them all using copy tftp flash
6. Once you have all files loaded in flash, do this:
   1. (config)#telephony-service
   2. (config-telephony)#load PhoneModelNumber FilenameWithAsterisk Example: (config-telephony)#load 7942 SCCP42.8-5-3S.loads (The documentation says to use the file extension for CUCME version >= 7.0.1, but I also saw something that said don’t. I tried both ways and it seemed to work. YMMV)
7. Once all that is done, reload your IP phone (either power cycle it or reset it through the IOS or CUCME GUI)
8. Ideally, the phone will see the new firmware configuration and proceed with the upgrade

Please note that there may be some caveats/prereq’s that I didn’t include here (I don’t think there are, but I didn’t triple check everything). As always, this worked for me, it may or may not work for you. Hopefully, it will.

I hope this serves as an easy to follow guide to upgrading the firmware on your Cisco IP phone. I’m sure for those of you that have done it many times, its rather simple. But for voice noobs such as myself, it was quite a PITA.

CCIE On Hold – CCVP In Play

So as much as I like the thought of “getting my numbers,” – I just can’t get back into it yet it seems. I’ve tried a few times, but for whatever reason, my mind isn’t working with me here. I don’t like having that feeling of something looming over me that I’m not actively working on. So instead of living what that feeling of “I should be doing xxxx to help move this along,” I’m switching paths…to the CCVP.

We recently brought up a satellite office on a call manager express set up, which will eventually tie into our main office when we roll it out later this year. We’re also migrating all of our (albeit only 3) remote offices to voice over IP, so I think that will help to keep me in good shape for the CCVP battery of tests.

While the CCIE R&S is generally just an expansion of the CCNP topics, I know very little about voice and related concepts. It will be nice learning completely new technologies, and not just revisiting stuff I already know somewhat, but need to learn in more depth. I’ve already ordered the CVOICE study guide and am working my way through that for now. So far, so good! It’s nice to be genuinely interested in the material again. Hopefully, I can pull this off by the end of the year…a little ambitious, but manageable I think. QoS may have its way with me though…we’ll see.

EtherChannel Negotiation for Dummies

Similar to my post on DTP negotiation, this is just my way of remembering the nuances of EtherChannel negotiation…

Mode On = No negotiation takes place

PAgP (Cisco proprietary)
Desirable: send PAgP packets
Auto: listen for PAgP packets
D+D = EtherChannel
D+A = EtherChannel
A+A = No EtherChannel

LACP (Industry standard)
Active: send LACP packets
Passive: listen for LACP packets
A+A = EtherChannel
A+P = EtherChannel
P+P = No EtherChannel

Carry on…nothing else much to see here.

http://ciscocertifiedhell.com/2009/07/31/dtp-negotiation-for-dummies/

Packet Racket

Also…new not-necessarily-Cisco related blog started at http://packetracket.wordpress.com I wanted to keep my CCIE studying/progress separate from non-Cisco stuff. It’s mostly tech related, but may contain the occasional personal rant/observation/etc.

Cheers!

The Day of Reckoning Approaches

Ok, so I’ve slacked off long enough. Munchkin isn’t sleeping well, but I can’t use that as an excuse to put off restarting studying forever.

I’ve given myself until my birthday (in a few weeks) to not think about it…and then, it is time! Time to get back in the packet groove. I’ve got my tentative study plan laid out here for others to use if they’d like. Its not final yet, and there are some holes to be filled, but at least I have a defined set of tasks to accomplish.

So, in the words of Eminem: “Let’s get down to business, I don’t got no time to play around, what is this, must be a circus
in town, let’s shut the shit down on these clowns, can I get a witness, {hell yeah}”

Ah hem…sorry ‘ bout that. My social filter malfunctioned.

NOTE: After going back into the INE online classroom, I’ve found that the ATC COD has changed for the v4 exam. The spreadsheet referenced above may contain some of the older ATC COD videos, but I am updating them as I go through them.

CCIblah

I’m having a hard time getting back into the studying habit since being away from it for so long. I know I want this, but damn if I can get my non-studying-ass in gear again. I read through all of these cool jobs and want them, but need an IE! *curses*

Anyhow, this is my attempt to convince myself back into studying…get back into the game, etc. It’s a long road, but it’s time to start back down it.

Things I need to do:

• Get a better system on which to run Dynamips/Dynagen
• Figure out I can squeeze in time during the week and develop a new study plan based on that
• Study and Lab!

Based on my v4 written, I need to focus on Multicast in a bad way…among other things.

Until next time…

Beta Results Came Back (Finally)

After almost exactly 8 weeks since I took the 350-001 beta, I got my results back. (See my previous post for the background on this)

I ended up with a 623, which given the little studying I did, makes me feel pretty good. Let’s just say that I really need to hit multicast pretty hard. So with the right amount of preparation, the written should be relatively simple..I hope.

I need to get back into the game here soon. The little one has somewhat of sleep schedule now, but it just doesn’t necessarily agree with my peak study times! (ie she’s awake around 4am — I’m still operating in zombie mode)

Reading through the success stories on ieoc.com has helped get my motivation going, now it’s just time to do something about it.

351-001 Beta Done and Over With

So, it wasn’t as painful as I thought it would be…had I put in the proper preparation, I would’ve been fine.  I have no doubts that on my “real” attempt, I will pass with no problem. I personally thought the test was easier than the BSCI, but I suppose it’s not a fair comparison.

Multicast was one of the topics that was covered more heavily it seemed…I really need to dig into that pretty heavily. As several people have mentioned, a few of the questions popped up several times, just in various formats. As a rough estimate, I’d say that about 70% of the topics on the written blueprint were addressed, which isn’t too bad.

If I had to guess, I’m estimating a 600 or so, which isn’t bad considering the severe lack of preparation. Anyhow…time for a break to regroup, focus on the upcoming munchkin arrival, and relax a bit. I’ll be back in full force sometime soon.

CCIE Written v4.0 Tomorrow!

Tomorrow, I get to look forward to finding out how poorly I did in 6-8 weeks. My main focus tomorrow will be on how the written exam is “written.” Basically, is it similar to the the CCNP exams, or is it something completely different. I suppose it’s not a great way to go about it, but I basically want to find out what’s on the test. I know that each version of the written will vary of course, but I guess the best way to phrase it is “How do they cram about 90 individual topics (on the blueprint) into 100 questions?”

Let’s see what happens! I am looking forward to a fresh start again though in a few months. Mad props to all of you who manage to pull off the CCIE while working and having a family! Once we find out what life with a newborn is like, I will be able to get a better idea of the (realistic) amount of time I can devote per day to studying and go from there.

I’ve learned that from the few short weeks I’ve been studying, I need to devote more time to each topic to completely understand it and master it. I started off by creating a pretty rigorous study schedule and found that as time went by, I would rush to finish reading the material just in order to keep up with “my schedule.” I know that I need to have some sort of time line to actually pull this off, but it needs to be realistic and allow me to grasp the material and not just “read it” for the sake of reading it.

I also think that I’ll revert back to my original strategy of studying for the lab, and taking the written sometime during that time. I’ve found that the layer 2 material I studied using a combination lab/reading approach has stuck with me much more than the material that I’ve simply just read through, and not really labbed out.

So, with all of that said…I’m checking out for now. I’ll post my thoughts on the beta written sometime later this week, but aside from that, I’m out until further notice and in final countdown for arrival of Baby Smurf.

Good luck to everyone in their studies!