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Ask questions and share experiences with SD-WAN and Session Smart Router (formerly 128T).
  • 1.  How services classes are mapped to a service

    Posted 04-11-2019 11:51
    Hi All,

    I have a question around how to simplify the attachment of service classes to services. 

    Myself and a colleague are currently building a network for an ISP, and our goal is to give them MPLS-like SLA and performance over multiple internet links. 

    Because this is an ISP and we will be transitting MPLS traffic, we will have to adhere to the QOS model that the ISP has implemented on their core network. We have configured 6 different service classes, which match what the ISP will be transitting. Then we created 6 different services for these classes to be mapped to. However, I see that service classes can only be applied to a specific service via a service policy. 

    Which means, in a deployment like this, we would have 6 service classes, 6 service policies and 6 services. But if I could map a service class directly to a service, this means I only need 6 service classes, 1 service policy, and 6 services. Is there an easier way of getting a service class mapped to a service, without the need of created extra service policies?

    Regards,

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    Morne Vermeulen
    Engineer
    +27 (0) 10 141 8512
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  • 2.  RE: How services classes are mapped to a service

     
    Posted 04-11-2019 13:52
    Hi Morne, thanks for the question.

    There's no way to remark these to different DSCP values than the "two layer" approach (service > service-policy > service-class), unless all of your traffic is received uniformly... i.e., all HTTPS traffic is marked one way, all SIP traffic is marked another way, etc. The 128T's marking happens in one of two ways: either by applying a service-policy/service-class to a service, or by "falling through" to a session-type. It sounds like you're familiar with the former, but maybe the latter can help?

    When you do NOT apply a service-policy/service-class to a service, then the 128T will look at the transport protocol and ports and try to classify that traffic as part of a session-type. E.g., UDP/5060 is SIP, TCP/443 is HTTPS, etc. (We have a bunch of these that come as part of your factory default configuration, but you can add any number of them on your own.) For each of these session-types, it'll also give you the opportunity to apply a service-class. Our built-in session-type for SIP uses the service-class "Signalling," which will cause SIP to get marked to DSCP 40.

    If this is the case, you can use one service to forward all of the traffic with a handful of session-types and service-classes.

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    pt.
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  • 3.  RE: How services classes are mapped to a service

    Posted 04-12-2019 05:08
    Hello,

    How to map a traffic which wasn't matched to any service and session-type? It is now showed as "Unclassified" in dashboards.

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    Ivan Minin
    Houston TX
    (346) 319-6699
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  • 4.  RE: How services classes are mapped to a service

     
    Posted 04-12-2019 06:10
    Hi Ivan, you'll need to configure it using one of the two techniques I mentioned. Either assign the service a service-policy, and that service-policy has a service-class associated with it, or create a series of session-type configuration for the various flavors of traffic you're passing through.

    Applying the configuration to a service will cause it to affect all traffic for that service -- which means you will get the same DSCP treatment for all packets that match the service irrespective of port, protocol, etc. Applying the configuration to a session-type will specifically match that port/proto combination.

    Note that when you have a service-policy > service-class assigned to a service, it will "win," even if there's a session-type that ALSO matches that traffic.

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    pt.
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  • 5.  RE: How services classes are mapped to a service

    Posted 04-12-2019 06:21
    Thanks @peetee

    Let's say for instance, I make use of this service-type classification method:
    1) Would packets being transmitted still have a DSCP value assigned to them upon egress?
    2) Would this method work if I map a service-policy to the service in question, but I don't select a service-class? Or does this service need to have "blanks" on service-policy and service-class for the traffic to fall back onto service-types?

    Regards,

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    Morne Vermeulen
    Engineer
    +27 (0) 10 141 8512
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  • 6.  RE: How services classes are mapped to a service

     
    Posted 04-12-2019 06:26
    Hi Morne,

    1. Yes, packets will still have a DSCP value assigned to them (don't forget to set rewrite-dscp to true on the ingress interface!)
    2. Yes, it'll still work. You can use the service-policy for other service-policy goodness. But if you assign a service-class to it, it'll take that as gospel and write packets using that service-class. As long as the service-class is blank, it'll fall back to using session-type configuration instead.

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    pt.
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  • 7.  RE: How services classes are mapped to a service

    Posted 04-12-2019 06:37
    That's great!

    So 128T does a form of traffic engineering by default? Because even if I didn't tick rewrite-dscp, it would still treat the different session-types as specified by default? 

    I also see that service classes by default have traffic classes selected, but by default there is no Traffic profile? Could you give me an idea of what the default split is for High/Medium/Low/BE in the 128T software?

    Regards,

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    Morne Vermeulen
    Engineer
    +27 (0) 10 141 8512
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  • 8.  RE: How services classes are mapped to a service

     
    Posted 04-12-2019 06:57
    Traffic engineering is not enabled by default, you need to turn it on within a device-interface (router > node > device-interface > traffic-engineering > enabled = true).

    I don't recall offhand what the default splits are for H/M/L/BE. I can look it up when I get to the office this morning unless someone here beats me to it :) 

    Paging



    ​​

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    pt.
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  • 9.  RE: How services classes are mapped to a service

     
    Posted 04-12-2019 07:52
    Hey @Morne!

    If a Traffic-Profile is not defined, then the default minimum guaranteed reservation of bandwidth is:
    High: 80%
    Medium: 10%
    Low: 9%
    Best-Effort: 1%
    I got that answer from @Michael Adams's post here: https://community.128technology.com/communities/community-home/digestviewer/viewthread?GroupId=67&MessageKey=9b56f28c-687d-4a67-ab24-c6dd3bab2b72&CommunityKey=a3c08933-8ef0-490a-9861-e91f17cfd1fa&tab=digestviewer

    I also want to point you to @Reid's infographic here: https://community.128technology.com/viewdocument/traffic-engineering-prioritization?CommunityKey=1cca2e49-ba26-471a-9522-f5ccd96c86fe&tab=librarydocuments
    I find it very helpful when figuring out what the 128T is going to do. 
    ​​

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    Justin Melloni
    Documentation/Training Specialist
    MA
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