OER/PFR

Hello, 

Can someone explain how this timer is being used and in what measurement intervals...ms, sec ect?

and what does @76 mean?

thanks,

 

Prefix                  State     Time Curr BR         CurrI/F         Protocol

                      PasSDly  PasLDly   PasSUn   PasLUn  PasSLos  PasLLos

                      ActSDly  ActLDly   ActSUn   ActLUn      EBw      IBw

                      ActSJit  ActPMOS  ActSLos  ActLLos

-------------------------------------------------------------------------------------------

10.43.252.0/24         OOPOLICY*      @76 1.1.1.1         Tu252           U       

                             118       42        0        0        0    14971

                              35       31        0        0        5        1

                               N        N

Comments

  • Breland,

    After reading your post, I was curious to what the asnwer was, so I started to do some research on the timers. I found some info, but I did not find anything that really broke down the "sh oer master prefix" table or discussed what the"@" symbol meant, but after diving deeper into the technology and doing some labs, I believe that I have the answer for you :-).

    I don't know what you configs are on the MC, but just curious, do you have periodic timers configured? If so, what you are seeing is your periodic timer countdown in seconds for the 10.43.252.0/24 traffic flow.

    By default, the MC only looks for an alternate path when an Out of Policy event occurs. Once you enable periodic timers, the timer counts down in seconds from the time that you specified and once the time elapses, the MC will evaluate the statistics for all of the exit interfaces on the BR, checking ot see if there is a better way out of the network for that traffic class. The MC will continue to do this check after the periodic countdown time expires...

  • My previous response came after observing the timer from a lab that I had a periodic timer configured, however I just did another lab and I noticed that there was "@" next to the countdown time as well and I didn't have athe periodic timer enabled, so...

    If you have the periodic timer enabled, cool, if not, that time that you see is for something else. From what I observe, the defualt timer is counting down from 90.

    Look at your configs and let me know if you have priodic timers configured. In the mean while, I will do some more research and labs to figure out what that timer is for.

  • JoeMJoeM ✭✭✭

    I have been trying to understand this better, The documentation is very limited.  But I think I have it now (using debug).

     

    The keywords are   PDP start timer  and  "Active Probe All"

     

              means that it is "probing on all exits"

                                    Table-legend even says "active probe all"

              Policy Decision Point (PDP) is the number shown (timer)

     

    =============DEBUG OUTPUT==========================

    So, I was playing with a prefix (150.1.6.0/24) by shutting EXTERNAL OER interfaces.  

    Normally the PDP start timer" begins at 90 secs.

    With some debugging I found this information, after shutting down access to the prefix: 

     

     

                 DEBUG OER MASTER PREFIX 150.1.6.0/24

    *Mar  1 03:18:34.439: OER MC PFX 150.1.6.0/24: TTC Prefix added
    *Mar  1 03:18:34.451: OER MC PFX 150.1.6.0/24: PDP start timer = 90 secs, prefix state = DEFAULT*
    *Mar  1 03:18:34.471: OER MC PFX 150.1.6.0/24: Prefix timeout, state DEFAULT*
    *Mar  1 03:18:34.479: OER MC PFX 150.1.6.0/24: APC Attempting to probe all exits

         partial output from     show oer master prefix

    150.1.6.0/24            DEFAULT*     73 U               U               U

    <snip snip snip>

    *Mar  1 02:43:45.427: OER MC PFX 150.1.6.0/24: Prefix timeout, state INPOLICY*
    *Mar  1 02:43:45.435: OER MC PFX 150.1.6.0/24: APC unable to stop probing on all exits
    *Mar  1 02:43:45.439: OER MC PFX 150.1.6.0/24: PDP choose exit, prefix state = INPOLICY*, 0
    *Mar  1 02:43:45.443: OER MC PFX 150.1.6.0/24: pfx bw 75, Exit bw
    *Mar  1 02:43:45.447: OER MC PFX 150.1.6.0/24: The prefix is unreachable from all exits.
    *Mar  1 02:43:45.451: OER MC PFX 150.1.6.0/24: Uncontrol prefix, Couldn't find the best exit
    *Mar  1 02:43:45.455: %OER_MC-5-NOTICE: Uncontrol Prefix 150.1.6.0/24, Couldn't find the best exit
    *Mar  1 02:43:45.459: OER MC PFX 150.1.6.0/24: PDP start timer = 90 secs, prefix state = DEFAULT*
    *Mar  1 02:43:45.463: OER MC PFX 150.1.6.0/24: Uncontrol prefix, Couldn't choose exit in prefix timeout
    *Mar  1 02:43:45.467: %OER_MC-5-NOTICE: Uncontrol Prefix 150.1.6.0/24, Couldn't choose exit in prefix timeout

    *Mar  1 02:43:45.471: OER MC PFX 150.1.6.0/24: PDP start timer = 390 secs, prefix state = DEFAULT*

         partial output from show oer master prefix


    150.1.6.0/24            DEFAULT*      318 U               U               U

     

    -----------------------------------------

    Here is the Cisco-DOC  Reference for PDP (policy decision point):

    "When running an PfR policy that compares the
    traffic class performance metrics with default or configured thresholds,
    a traffic class may change state. PfR uses a policy decision point
    (PDP) that operates according to the traffic class state transition
    diagram shown in Figure 5. The state transition diagram in Figure 5 contains the following states:

     

     

  • Good stuff Joe :-).

    I noticed that the timer was counitng down from 90, but I couldn't find what exactly that timer was for... As I mentioned in my previous post, I noticed when you have periodic timers enabled, it uses the "@" symbol as well.

    Thanks for the info!

  • JoeMJoeM ✭✭✭

    Good stuff Joe :-).

    I noticed that the timer was counitng down from 90, but I couldn't find what exactly that timer was for... As I mentioned in my previous post, I noticed when you have periodic timers enabled, it uses the "@" symbol as well.

    Thanks for the info!

    Glad this helped.   I went a little further down the OER/PFR rabbit-hole for this info.      ;-)

  • JoeMJoeM ✭✭✭

    Here are more snippets from  the debug.  

    PDP is like a policeman in an intersection, making decisions for the different states.

     

                                       debug oer master prefix

     

    Notice that the PDP sets the timer for every prefix state. It also announces the state (end and beginning).

    OER MC PFX 150.1.140.0/24: Prefix timeout, state DEFAULT*
    OER MC PFX 150.1.140.0/24: PDP choose exit, prefix state = DEFAULT*, 0
    OER MC PFX 150.1.140.0/24: Check ACT REL unreachable: unreachable 0, policy 50%, notify FALSE
    OER MC PFX 150.1.140.0/24: Check ACT ABS delay: delay 24, policy 200, notify FALSE
    OER MC PFX 150.1.140.0/24: Best exit is 150.1.1.1 Se0/0, based on util
    OER MC PFX 150.1.140.0/24: Start FWD on new exit, br =
    150.1.1.1, i/f = Se0/0, nexthop 0.0.0.0, seq 1707, proto 4, exact TRUE
    OER MC PFX 150.1.140.0/24: PDP start timer = 15 secs, prefix state = CHOOSE
    OER MC PFX 150.1.140.0/24: prefix_status 0 received, br = 150.1.1.1 i/f = Se0/0
    OER MC PFX 150.1.140.0/24: PDP start timer = 300 secs, prefix state = HOLDDOWN


                                partial output    show oer master prefix

    150.1.140.0/24          HOLDDOWN      283    150.1.1.1       Se0/0           BGP

     

     

                               Finally.....after 300secs (HOLDDOWN)

    OER MC PFX 150.1.140.0/24: Prefix timeout, state HOLDDOWN
    OER MC PFX 150.1.140.0/24: PDP choose exit, prefix state = HOLDDOWN, 0
    OER MC PFX 150.1.140.0/24: Check PASS ABS delay: delay 0, policy 200, notify FALSE
    OER MC PFX 150.1.140.0/24: PDP no start timer, prefix state = INPOLICY


                                partial output   show oer master prefix

    150.1.140.0/24          INPOLICY        0    150.1.1.1       Se0/0           BGP

    ------------------------------------------------------

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