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Poxy OSI Model

Discussion in 'General Chat' started by Caesium, Mar 9, 2007.

  1. Caesium
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    Caesium My BM is fixed!

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    God I hate reading about this **** because the people that write it never seem to make any common sense!

    God damn VOIP..!
    #1
  2. tiptonjuk
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    tiptonjuk Member

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    If you think VOIP is bad, try getting it to work through a firewall with NAT, that will really blow your mind!
    #2
  3. dickys3
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    dickys3 Moderator Staff Member Moderator

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    The OSI model is not the easiest subject to learn, but once you "get it", it will make a hell of a difference to properly understanding networking.

    Stick with it!
    #3
  4. Caesium
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    Caesium My BM is fixed!

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    The systems we install will not work behind a firewall, even the manufacturers state they should not be behind one.

    You can however use the system itself to firewall against outside attacks and also use it as a NAT or put it on a VLAN.

    Getting a VoIP network to work over NAT isn't in itself that hard, just need to get the routing tables correct
    #4
  5. batwad
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    batwad Member

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    The problem I always had with the OSI model is the way it's taught, by which I mean that it's usually "these are the layers and this is what they do, memorise it". The model itself is ****. The useful thing to learn from it is the principle of tiers and layers when modelling and designing stuff.

    I mean, who really cares whether I can remember if the transport layer is above or below the security layer? Bag of arse.
    #5
  6. Caesium
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    Caesium My BM is fixed!

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    I see you took notice, where did the security layer come from? made it up didn't you!
    #6
  7. Caesium
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    Caesium My BM is fixed!

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    Now i'm up to the whys and wherefors of Latency and Jitter (not dance moves)
    #7
  8. C_Audiboy
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    C_Audiboy Vroom Vroom

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    Hey hey at last someone as geeky as me!

    What kind of VoIP systems are you working on?

    I do a lot of Cisco Callmanager installations, but am looking at some newer more cost effective SIP-based solutions. Some customers just can't pay the inflated Cisco prices for licenses!

    VoIP servers behind firewalls are very common for larger enterprise customers, almost a pre-req now to install a failover pair along with the new VoIP servers. As long as you have the correct ports, the firewall is stateful and has some application inspection capabilities it should be able to handle the traffic correctly.
    #8
  9. Caesium
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    Caesium My BM is fixed!

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    We install Avaya IPO and Siemens HiPath.
    The only problem we encounter with firewalls is when we don't manage them or if they're ****. They can cause all sorts of latency problems.
    #9
  10. C_Audiboy
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    C_Audiboy Vroom Vroom

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    Yeah suppose your right.

    I've done a few installs with thousands of IP phones on the other side of a firewall from the IPT servers, and never had an issue. Like you say all down to the firewall hardware and the config (along with many other 'customer' factors of course!)

    Every install is different though, as I'm sure you'll know!
    #10
  11. Caesium
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    Caesium My BM is fixed!

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    We're looking to buy an Optiview III network analyser if I can justify it.
    Ever done any MPLS work?
    #11
  12. Caesium
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    Caesium My BM is fixed!

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    Such as?
    #12
  13. C_Audiboy
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    C_Audiboy Vroom Vroom

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    A very nice package called 'SipCat' based on Asterisk with a nice GUI.

    Tics most of the boxes at a fraction of the price of Cisco equivalent IPT kit.

    (hey wait a minute you might be my competition ;) )
    #13
  14. Caesium
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    Caesium My BM is fixed!

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    Sounds like a softswitch to me, a bit like Swyx
    #14
  15. C_Audiboy
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    C_Audiboy Vroom Vroom

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    Yup, all 'softswitch' stuff, same as Cisco Callmanager.
    #15
  16. Caesium
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    Caesium My BM is fixed!

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    So do you work for a company or for yourself?

    Up to Pulse Code Modulation now.
    Nyquist Theorem.
    #16
  17. C_Audiboy
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    C_Audiboy Vroom Vroom

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    Oh no luck mate!!

    I used to work for a large integrator but a few of us recently broke away, taking a few of the customers with us.

    Its been great so far - no managers to piss us off!! We just get the job done, and get paid a nice rate for doing it.
    #17
  18. Caesium
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    Caesium My BM is fixed!

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    Hope it continues going well for you! I work for a small company, but they have the right idea.
    #18
  19. batwad
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    batwad Member

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    See what I mean? Never done me any harm ;)

    Maybe I'm getting it confused with the OSI operating system model, rather than the network one; I'm fairly sure there's a security layer in that. Mind you, I though they added a security layer to the network model, what with IPSec and all that jazz :think:
    #19
  20. inigoj
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    inigoj Member

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    lol, reminds me of my degree days.

    It was when i started dreaming JAVA code that i decided software engineering wasnt for me.
    #20
  21. OutLore
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    OutLore VOIP Dude

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    Well you Call Manager guys, let me know if you need any applications for CCM/CCME, that's what I do :) We are a Cisco Technology Development partner, some of our products are on the solutions plus system.

    Operator Consoles, low cost ACD funcionality, call billing, call recording, corporate directories etc etc
    #21
  22. C_Audiboy
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    C_Audiboy Vroom Vroom

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    Good to know!!!

    Who do you work for? We're looking at getting hold of a decent wallboard application for real-time queue and agent stats for a couple of IPCC express customers we have. Not rocket science I know but the customers love these things.

    You do anything like that?

    Also what are the operator consoles like (I've done a few ARC installs - these are not too bad).
    #22
  23. OutLore
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    OutLore VOIP Dude

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    That's me :)
    #23
  24. C_Audiboy
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    C_Audiboy Vroom Vroom

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    Ha ha ha....... small world indeed. I was at your office in Reading just over a year ago.

    So what do you do for ARC exactly? More importantly can you get my company any discounts :eyebrows:
    #24
  25. OutLore
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    OutLore VOIP Dude

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    Yeah, funny how people show up here and there...

    So who do you work for?

    I'm a (the) Technical Services Consultant - basically handling system design, implementation, support escalations etc.

    Might have a job change soon though - just got back from the USA after a year out there, landed this morning and straight into work....
    #25

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