Network Design Challenge

PHYSICAL TOPOLOGY

       LOGICAL TOPOLOGY

Recently one of the customer I am working for came up with an interesting requirement.

Current customer setup look alike something similar to topology (logical) given above. Customer has two locations per say connected through back to back T1 Circuits. In current setup R1-R3 is the primary path, and if a failure occurs in that case traffic should fall back to backup path using R2-R4. Customer is using One HSRP group on each side for auto failover purpose and currently static routing is in place.
 
So considering all this, following is how over all traffic flow looks like at the moment from A to C and from B to C perspective:
 

Hmmm... sounds like a pretty flat and easy network... isn't it ? :-)


Now here is the new requirement: As you guys can see we are wasting our bandwidth here on the backup circuit between R2-R4. And Bandwidth in our real life means $$$$$$ :-)

So here is new desired flow: When Host A talks to Host C, It should use Path through R1-R3. At the same time if Host B talks to Host C, It should use Path through R2-R4. At the same time both links should be redundant for each other for all traffic flow. So based on this requirement , the traffic flow needs to look like following:

As you can see , we need to account 8 potential FAILURE DOMAINS to ensure our fail-over scenarios works just fine. 

Also requirement is to ensure we don't have any asymmetric routing into the network. And of course NO dynamic routing protocol should be introduced.

So how you gonna do this ? :-) , since from very high level perspective it looks very easy. But it ain't :-)

            
Current Configuration
++++++++++++++                                                                                                                        
SW-A
=====
!
en
!
conf t
!
ho SW-A
!
no ip do lo
!
no cdp run
!
ip routing
!
int f1/1
 sw mo acc
 sw acc vl 10
 exit
!
int vlan 10
 ip add 10.0.0.1 255.255.255.0
 no sh
 exit
!
ip route 20.0.0.0 255.255.255.0 12.0.0.1
ip route 30.0.0.0 255.255.255.0 12.0.0.1
!
int f1/0
 no switchport
 ip add 12.0.0.2 255.255.255.0
 no sh
 exit
!
end

!


SW-B
=====
!
en
!
conf t
!
ho SW-B
!
no ip do lo
!
no cdp run
!
ip routing
!
int f1/0
 no switchport
 ip add 34.0.0.2 255.255.255.0
 no sh
 exit
!
int f1/1
 sw mode access
 sw acc vl 20
 exit
!
int f1/2
 sw mode access
 sw acc vl 30
 exit
!
int vlan 20
 ip add 20.0.0.1 255.255.255.0
 no sh
 exit
!
int vlan 30
 ip add 30.0.0.1 255.255.255.0
 no sh
 exit
!
ip route 0.0.0.0 0.0.0.0 34.0.0.1
!
end
!

R1
====
!
en
!
conf t
!
ho R1
!
no ip do lo
!
int f0/0
 ip add 12.0.0.111 255.255.255.0
 standby 1 ip 12.0.0.1
 standby 1 pri 105
 standby 1 pree
 standby 1 track s1/0
 exit
!
int s1/0
 ip add 13.0.0.1 255.255.255.0
 encap ppp
 no sh
 exit
!
ip route 20.0.0.0 255.255.255.0 13.0.0.3
ip route 30.0.0.0 255.255.255.0 13.0.0.3
ip route 0.0.0.0 0.0.0.0 13.0.0.3
!
ip route 10.0.0.0 255.255.255.0 12.0.0.2
!
end
!


R2
===
!
en
!
conf t
!
ho R2
!
no ip do lo
!
no cdp run
!
int f0/0
 ip add 12.0.0.112 255.255.255.0
 standby 1 ip 12.0.0.1
 standby 1 pree
 no sh
 exit
!
int s1/0
 ip add 24.0.0.2 255.255.255.0
 encap ppp
 no sh
 exit
!
ip route 20.0.0.0 255.255.255.0 24.0.0.4
ip route 30.0.0.0 255.255.255.0 24.0.0.4
ip route 0.0.0.0 0.0.0.0 24.0.0.4
!
ip route 10.0.0.0 255.255.255.0 12.0.0.2
!
end
!

R3
===
!
en
!
conf t
!
ho R3
!
no ip do lo
!
no cdp run
!
int f0/0
 ip add 34.0.0.3 255.255.255.0
 standby 1 ip 34.0.0.1
 standby 1 pri 105
 standby 1 pree
 standby 1 track s1/0
 no sh
 exit
!
int s1/0
 ip add 13.0.0.3 255.255.255.0
 encap ppp
 no sh
 exit
!
ip route 10.0.0.0 255.255.255.0 13.0.0.1
ip route 0.0.0.0 0.0.0.0 13.0.0.1
!
ip route 20.0.0.0 255.255.255.0 34.0.0.2
ip route 30.0.0.0 255.255.255.0 34.0.0.2
!
end
!
 

R4
===
!
en
!
conf t
!
ho R4
!
no ip do lo
!
no cdp run
!
int f0/0
 ip add 34.0.0.4 255.255.255.0
 standby 1 ip 34.0.0.1
 standby 1 pree
 no sh
 exit
!
int s1/0
 encap ppp
 ip add 24.0.0.4 255.255.255.0
 no sh
 exit
!
ip route 10.0.0.0 255.255.255.0 24.0.0.2
ip route 0.0.0.0 0.0.0.0 24.0.0.2
!
ip route 20.0.0.0 255.255.255.0 34.0.0.2
ip route 30.0.0.0 255.255.255.0 34.0.0.2
!
end
!

So let's see who among you is a Real Network Warrior  :-)

Final Config

R1
====

!
en
!
conf t
!
ho R1
!
no ip do lo
!
ip sla 2
 icmp-echo 34.0.0.3 source-interface f0/0
 freq 5
 timeout 5000
 exit
!
ip sla schedule 2 life forever start-time now
!
track 2 rtr 2 reachability
!
int f0/0
 ip add 12.0.0.111 255.255.255.0
 standby 1 ip 12.0.0.1
 standby 1 pri 105
 standby 1 pree
 standby 1 track s1/0
 standby 1 track 2
 standby 2 ip 12.0.0.11
 standby 2 pree
 no sh
 exit
!
int s1/0
 ip add 13.0.0.1 255.255.255.0
 encap ppp
 no sh
 exit
!
ip route 20.0.0.0 255.255.255.0 13.0.0.3
ip route 0.0.0.0 0.0.0.0 13.0.0.3
!
ip route 10.0.0.0 255.255.255.0 12.0.0.2
!
end
!





R2
===

!
en
!
conf t
!
ho R2
!
no ip do lo
!
no cdp run
!
ip sla 1
 icmp-echo 34.0.0.4 source-interface s1/0
 time 500
 freq 3
 exit
!
ip sla schedule 1 life forever start-time now
!
track 2 rtr 1 reachability
!
int f0/0
 ip add 12.0.0.112 255.255.255.0
 standby 1 ip 12.0.0.1
 standby 1 pree
 standby 2 ip 12.0.0.11
 standby 2 pri 105
 standby 2 pree
 standby 2 track 2
 no sh
 exit
!
int s1/0
 ip add 24.0.0.2 255.255.255.0
 encap ppp
 no sh
 exit
!
ip route 30.0.0.0 255.255.255.0 24.0.0.4
ip route 0.0.0.0 0.0.0.0 24.0.0.4
!
ip route 10.0.0.0 255.255.255.0 12.0.0.2
!
end
!


SW-A
=====

!
en
!
conf t
!
ho SW-A
!
no ip do lo
!
no cdp run
!
ip routing
!
int f1/1
 sw mo acc
 sw acc vl 10
 exit
!
int vlan 10
 ip add 10.0.0.1 255.255.255.0
 no sh
 exit
!
ip route 20.0.0.0 255.255.255.0 12.0.0.1
ip route 30.0.0.0 255.255.255.0 12.0.0.11
!
int f1/0
 no switchport
 ip add 12.0.0.2 255.255.255.0
 no sh
 exit
!
end
!



R3
===


!
en
!
conf t
!
ho R3
!
no ip do lo
!
no cdp run
!
int f0/0
 ip add 34.0.0.3 255.255.255.0
 standby 1 ip 34.0.0.1
 standby 1 pri 105
 standby 1 pree
 standby 1 track s1/0
 no sh
 exit
!
int s1/0
 ip add 13.0.0.3 255.255.255.0
 encap ppp
 no sh
 exit
!
ip route 10.0.0.0 255.255.255.0 13.0.0.1
ip route 0.0.0.0 0.0.0.0 13.0.0.1
!
ip route 20.0.0.0 255.255.255.0 34.0.0.2
ip route 30.0.0.0 255.255.255.0 34.0.0.2
!
ip route 24.0.0.0 255.255.255.0 34.0.0.4
!
access-l 100 permit ip 30.0.0.0 0.255.255.255 10.0.0.0 0.255.255.255
!
ip sla 1
 icmp-echo 24.0.0.4 source-ip 34.0.0.3
 timeout 5000
 frequency 3
!
ip sla schedule 1 life forever start-time now
!
ip sla 3
 icmp-echo 12.0.0.112 source-interface FastEthernet0/0
 frequency 5
!
ip sla schedule 3 life forever start-time now
!
track 1 rtr 1 reachability
!
track 3 rtr 3 reachability
!
track 2 list boolean and
 object 1
 object 3
!
route-map PBR per 10
 match ip address 100
 set ip next-hop verify-availability 34.0.0.4 1 track 2
route-map PBR per 20
 exit
!
int f0/0
 ip policy route-map PBR
 no ip route-cache cef
 exit
!
ip sla 5
 icmp-echo 12.0.0.111 source-interface Serial1/0
 frequency 5
 timeoute 5000
!
ip sla schedule 5 life forever start-time now
!
track 5 rtr 5 reachability
!
int f0/0
 standby 1 track 5
 exit
!
end
!



R4
===

!
en
!
conf t
!
ho R4
!
no ip do lo
!
no cdp run
!
int f0/0
 ip add 34.0.0.4 255.255.255.0
 standby 1 ip 34.0.0.1
 standby 1 pree
 no sh
 exit
!
int s1/0
 encap ppp
 ip add 24.0.0.4 255.255.255.0
 no sh
 exit
!
ip route 10.0.0.0 255.255.255.0 24.0.0.2
ip route 0.0.0.0 0.0.0.0 24.0.0.2
!
ip route 20.0.0.0 255.255.255.0 34.0.0.2
ip route 30.0.0.0 255.255.255.0 34.0.0.2
!
end
!





SW-B
=====


!
en
!
conf t
!
ho SW-B
!
no ip do lo
!
no cdp run
!
ip routing
!
int f1/0
 no switchport
 ip add 34.0.0.2 255.255.255.0
 no sh
 exit
!
int f1/1
 sw mode access
 sw acc vl 20
 exit
!
int f1/2
 sw mode access
 sw acc vl 30
 exit
!
int vlan 20
 ip add 20.0.0.1 255.255.255.0
 no sh
 exit
!
int vlan 30
 ip add 30.0.0.1 255.255.255.0
 no sh
 exit
!
ip route 0.0.0.0 0.0.0.0 34.0.0.1
!
end
!

HTH...
DEEPAK ARORA
Evil CCIE

Frame-Relay Challenge 2 - Solution

So welcome back and now it's time to reveal the solution for challenging Frame-Relay challenge.


Today I am little short of time so just going to show up the configuration, verification and troubleshooting part in sequence without much of explanation. Also I believe that the all three parts(configuration, verification & troubleshooting) are very much self explanatory and most of the people won't be having problem to understand it. But in-case someone has some doubt or want to discuss something in this regards, please feel free to drop me an email at - deepakarora.1984@gmail.com


and have a nice weekend :-) 


Also no lucky winner so far with right configs (both challenges)  :-(


Will post one RIP challenge on Monday morning as someone recently asked me for it --- Watch out for that on monday Manish :-)


Here we are with configs now :


****************
*CONFIGURATION*
****************

The only way to meet the first objective is using concept of PPP Over FR.

*************

*VERIFICATION*

*************

Here you are looking at magic of PPP Peer Neighbor Route Feature.

Lets verify Spoke To Spoke Reachability.

******************

TROUBLESHOOTING

******************

The config shown in notepad has to be done on R2, R3 & R4 in order to establish full reachability. The reason I showed notepad config here to share the fact that when we are supposed to do similar configs like this on multiple routers, in that case notepad can be very handy and can save a lot of time during configuration section of Lab.


HTH...
Deepak Arora