Friday, May 31, 2013

Learning Prefixes on the OER Master Controller (MC) - Part 2

I enable learning on the OER Master.

oer master

I examine the ‘Learn Settings’s 

R4#s oer master | b Learn Settings

Learn Settings:
  current state : SLEEP
  time remaining in current state : 6957 seconds
  no delay
  no inside bgp
  no protocol
  monitor-period 5
  periodic-interval 120
  aggregation-type prefix-length 24
  prefixes 100
  expire after time 720

I notice the OER Master is 'sleeping' i.e. not learning prefixes. By default the OER master learns for 5 mins and then sleeps for 120 minutes!  To increase the frequency of OER master learning from the default settings I adjust the monitor period (length of time MC learns prefixes) and the periodic-interval (time between monitoring periods).

oer master
monitor-period 1
periodic-interval 0

I generate some traffic from the MC to R9

ip sla 1
 frequency 10
ip sla schedule 1 life forever start-time now
ip sla 2
 tcp-connect 23 source-ip
 timeout 500
 frequency 2
ip sla schedule 2 life forever start-time now

On R9
Ip sla responder

I now check the MC is learning about this prefix

R4#show oer master prefix learned throughput
OER Prefix Statistics:
 Pas - Passive, Act - Active, S - Short term, L - Long term, Dly - Delay (ms),
 P - Percentage below threshold, Jit - Jitter (ms),
 MOS - Mean Opinion Score
 Los - Packet Loss (packets-per-million), Un - Unreachable (flows-per-million),
 E - Egress, I - Ingress, Bw - Bandwidth (kbps), N - Not applicable
 U - unknown, * - uncontrolled, + - control more specific, @ - active probe all
 # - Prefix monitor mode is Special, & - Blackholed Prefix
 % - Force Next-Hop, ^ - Prefix is denied

Prefix                  State     Time Curr BR         CurrI/F         Protocol
                      PasSDly  PasLDly   PasSUn   PasLUn  PasSLos  PasLLos
                      ActSDly  ActLDly   ActSUn   ActLUn      EBw      IBw
                      ActSJit  ActPMOS  ActSLos  ActLLos
--------------------------------------------------------------------------------             INPOLICY*        0         Fa0/1           U    
                             123      127        0        0        0        0
                               U       75        0        0        1        1
                               N        N

My next post is on how to get the MC to choose the best route.

Thursday, May 30, 2013

OER MC Best Route Selection - Part 3

From the Master Controller R1 I trace to the loopback of R9.  It can be seen I have two valid paths: one via R4 and one via R5. 


Type escape sequence to abort.
Tracing the route to

  1 84 msec 72 msec 56 msec
  2 72 msec 72 msec 56 msec
  3 [AS 2] 88 msec [AS 2] 120 msec *

I now enable oer 'route control' on the master. I also configure 'select exit best'.

oer master
mode route control
mode select-exit best

After a few minutes i notice the master has selected a best exit via R4. It achieves this by adjusting the bgp local preference.

s ip bgp
BGP routing table entry for, version 7
Paths: (2 available, best #2, table Default-IP-Routing-Table)
Multipath: iBGP
  Not advertised to any peer
  2 (metric 110) from (
      Origin incomplete, metric 409600, localpref 100, valid, internal
  2 (metric 20) from ( IP BG
      Origin incomplete, metric 409600, localpref 5000, valid, internal, best

 I now trace to R9 again and can see the path taken is the OER selected best route.

Type escape sequence to abort.
Tracing the route to

  1 28 msec 44 msec 32 msec
  2 36 msec 56 msec 32 msec
  3 [AS 2] 36 msec *  72 msec