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VoIP compared with VoMPLS

Viewing 15 posts - 1 through 15 (of 34 total)
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    Eduardo Polanco

    Any one out there that has done some studies on VoMPLS compared til VoIP?

    Im looking for some documents that studies both technologies… ups and downs on each subject…

    any help would be of great interest.

    regards Eduardo


    im not sure what you mean. MPLS is a mechanism to switch packets to different paths using “tags”.

    If you were going to do voice over this transport mechanism, then wouldnt you encapsulate it in ip/udp/rtp and send it along the path, allow the label edge to tag it and the label switch to switch it.

    Eduardo Polanco

    VoMPLS is a new standard for transporting Voice over the internet. Check out:

    Any more questions R ?



    R’s right. MPLS is a mechanism used to improve QoS. It’s not a protocol for transporting media per se.

    So you’re not comparing like for like.

    Trust “R”. He’s an author and works for one of the largest network equipment providers in the world. He’s a smart cookie and regularly contributes valuable advice to this forum.

    Eduardo Polanco

    Well 🙂

    If anyone know what I meen..

    There are two commonly discussed ways to transport voice over MPLS.

    VoIP over MPLS :
    wrapping voice in RTP/UDP/IP (VoIP) followed by encapsulation in the MPLS protocol.

    Voice directly over MPLS (VoMPLS):
    In this case the typical protocol stack would consist of voice samples encapsulated in the MPLS protocol on top of an MPLS transport arrangementsuch as FR,ATM,PPP.. or Ethernet…

    My question is…
    Have anyone in this forum done any studies (or thoughts) on VoMPLS ? and maybe compared it to VoIP ?

    any thoughts about the subject is interresting for me…


    You’re right; I’m sorry Eduardo.

    The MPLS Forum issued a press release that can be read at

    I don’t know anything about VoMPLS though, so I echo Eduardo’s question: anyone have any experience?



    What is the main reason for your interest ? Academic or commerial ?

    Jose Quintero


    You are right,

    There are some differences, between VoIP and VoMPLS.

    1a.- VoIP is voice over IP packet, where the Payload is encapsulated with its RTP/UDP Overhead on IP PAckets.

    1B.- VoMPLS is Voice Over MPLS Packet, wher the payload is encapsulated on a packet with MPLS Overhead (Not RTP/UDP Overhead), because is not and IP Packet.

    2a.- Voip, could be use din every environment, LAN, WAN, PC, MG, RGW, an soft application.

    2b.- VoMPLS, is only to trasport voice stream over a Pure MPLS Network for Trunking Application basically. to do that the new generation of media gateway will do two fuctions, the first one, to code the Analog Voice and convert it to a digital stram, and the second fuction will be a LER (Because each voice stream, will be encapsulated in a packet in a corresponding LSP).

    3a.- With Voip using a G.723.1 coded, you will need a least 17 Kbps of bandwidth for one channel

    3b.- With VoMPLS you will neen only 8,5 Kbps, due a redcution of IP Overhead.

    There aree more differeces but this space is to small to explain it




    Gabi :

    Im working on a thesis that is a part of the Graduate degree ( in Information and Communication Technology (ICT) at Agder University College (HiA). ( )

    Thats my main reason for asking.

    -But my personal interests are internet protocols, networkin and securety (IDS,Firewalling.. ect.)



    Jose Quintero :

    I appreciate very much that you’re sharing your knowledge on the subject.
    If you want to, Ill be more than happy if you have any web links for me, or if you personally want to share more of your knowledge. The thesis that I’m working on, is to be presented in June 2002. That leaves me a lot of time to study the subject thoroughly.
    Any help would be much appreciated, and of course your will be mentioned in the final reportJ.

    Jose Quintero


    This iss my email


    Sorry I jumped back onto this very late.
    Jose’ s points are great…thank you for helping educate me on the subject. I sometimes lose sight of other developments outside of VoIP.
    That being said, another issue I see is the ability to make VoMPLS extensible into data applications.
    When we talk about doing any type of multimedia application, we must always ask ourselves why?
    Sure a converged network is great, but what will make it pervasive.
    Since MPLS for all intensive purposes is a transport, we will lack some of the benefits of applications to enhance our communications.
    Until desktop machines are MPLS enabled, where am I going to get my voice on my PC that communicates through my messenger application, which btw I can also use that messenger app on my cell phone. How would I create interactive video applications without the edge enabled with MPLS?
    Just some quick thoughts.
    I would love to banter with you folks some more about this and other topics along these lines. Please include me on your thread.

    Jose Quintero


    Your concerns are valid. Due the MPLS technology is not enabled for workstation, only for access/edge.

    However, the operator will have a lot of benefit in the reduction of bandwidth, and they could justify onecanaig a MPLS Ntework with another application fifferente from VPN, and LEgacy over MPLS.

    For a While, we will not have VoMPLS at the en user, it is not the goal of VoMPLS.

    But, the future could bring everything.




    Like all technologies, it has its place, bandwidth reduction is a very viable requirement. I may just be a little short sided as I have mainly dealt with VoIP and have heard many carriers state that bandwidth is not one of their primary concerns.

    Carriers are usually concerned about money, and how much they can make. w/o those value added features, its VoMPLS becomes less of a value proposition. Now if there was a method proposed to transcode the different packet types VoMPLS – VoIP, this could be very attractive.



    Rick Gallaher

    Hello all,

    The Voip Standards and VoMPLS do not compete; they are ships in the night so to speak.

    You will need Voip Standards in all Lans, and Mans,and Telcointerface.

    Where these networks contact a WAN you may have to interface to MPLS where the Voip channels will be assigned into a FEC and a tunnel and treated with QoS paramters for real-time messages.

    To see more about MPLS please see

Viewing 15 posts - 1 through 15 (of 34 total)
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