Task 2.7 - What with the redistribution?

Why do we need to redistribute OSPF into BGP on R6?

Task asks that we configure AS 200 (R1 and R2) such that 54:1 prefers R3-R1 and X:3 prefers R3-R2.

The SG then shows redisting all OSPF into BGP on R6, but filtering it from being sent to R1. Seriously, I don't get it. Only thing it could be for is reachability - which isn't part of the task requirements 

Comments

  • Very strange indeed. If anyone has any idea, I'd like to hear it!

    Eric

  • Agree, I guess this relates a non mentioned task that  BB1 and BB3 should have BGP reachability to our internal networks and so those network advertised outside should not be advertised back inside via BGP. 

    Makes sense but really not asked for.

    Tom

  • It was not part of this task requirement but remember in the lab instructions, it states:

    image

    Full reachability is almost "always" a requirement in the R&S exam.

    This would be a good question for the proctor. Like "Hey mister proctor, do I have to make sure that AS54 prefixes are reachable by other devices in the network? "

    HTH

     

  • Hmm, got caught out on this task with the redistribution. However I was expecting a question later on to tell me this needs to be done

  • Hmm, got caught out on this task with the redistribution. However I was expecting a question later on to tell me this needs to be done


    The reachability requirement sometimes need you to redistribute certain routes that are not explicitly required. TCL script is definitely a great help to see whether we need to do this.

  • True that, though it makes me wonder whether I should be running thr TCL script after each section? Usually in the IGP section there will be a part which states "Redistribute so all devices have full reachability" - I was expecting a seperate task to come up and ask this

  • it makes me wonder whether I should be running thr TCL script after each section?

    In my exam, I used TCL after IGP Redistribution task and after I completed the whole tasks. And one more time after I re-verify the whole tasks. When I reverify the whole tasks, I did change certain things which I missed out and was an implicit requirement related to the lab general objective.

    I don't think you should run TCL every time you complete a task, it will kill you in the battle field >_<

    Happy studying!

  • True that, though it makes me wonder whether I should be running thr TCL script after each section? Usually in the IGP section there will be a part which states "Redistribute so all devices have full reachability" - I was expecting a seperate task to come up and ask this

    I used TCL script after finishing IGP part and traceroute if there are multiple exit point from one IGP domain to another to verify the incoming and outgoing path.

    Yes, on my daily SP practice also I use TCL script.

    HAPPY STUDY

    [:D]

  • Hi mellowd,

       You might not have specific redistribution task, but have a general initial requirement to make sure end-to-end connectivity is achieved by means of redistribution. I would run a TCL script after the IGP section is finished, and once again in the end to make sure i still have connectivity after rest of the tasks have been configured.

    Good luck with your studies!

  • I used TCL script after finishing IGP part and traceroute if there are multiple exit point from one IGP domain to another to verify the incoming and outgoing path.

    Yes, on my daily SP practice also I use TCL script.

    Agree, we should practice using TCL every time we are labbing VOL II / III / Mock lab. By only practising we can master the skill.

  • Hi,

    That's why I recommend TCL script for CISCO IOS book:

    http://www.ciscopress.com/bookstore/product.asp?isbn=1587059452

    HAPPY STUDY

    [:D]

  • Is it not overkill for CCIE Lab Exam? [:|]

  • It looks overkill to me :) I mean I wanted to know that much of TCL, but for the lab exam, a simple TCL for ping will work.

    Just my 2 cents.

  • Is it not overkill for CCIE Lab Exam?

    To make easy life when you are working in SP environment!!! Not for exam.

    For exam:

    R1#tclsh
    R1(tcl)#foreach ip {
    +>(tcl)#1.1.1.1
    +>(tcl)#2.2.2.2
    +>(tcl)#3.3.3.3
    +>(tcl)#} { ping $ip so lo0 time 1 }

    Isn't enough?

    HAPPY STUDY

    [:D]

  • R1#tclsh
    R1(tcl)#foreach ip {
    +>(tcl)#1.1.1.1
    +>(tcl)#2.2.2.2
    +>(tcl)#3.3.3.3
    +>(tcl)#} { ping $ip so lo0 time 1 }

    Isn't enough?

    Yup, this simple TCLSH is the one that I used in my exam, except I don't use parameter "time 1"  
    Sh ip alias on each device -> Put the IP addresses under TCLSH script -> paste it in TCLSH in each device and watch, and take note which is failing, then use show ip route, traceroute, fix IGP and ask proctor to confirm a doubt

  • I don't use time 1 either, but I do use repeat 3..so you don't have to wait for all the 5 pings to go through..

  • But why redistribute, why not just advertise a summary route, advertise one of the R6 networks, then summarize?

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