Tuesday, March 24, 2015

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Policy-Based Routing IP-SLA (Part-2 CCNP)

Ø  SLA Stands for Service Level Agreement
Ø  Allow us to understand the health of  the network along with particular route
Ø  Also allow us to automatically forwards the traffic if one ISP is down to other ISP if we have redundant ISP Connections
Ø  In this scenario we have two ISP Connection coming to our Enterprise Network

1st Step: - IP-SLA Configuration:-
Ø  Ping                            {ISP1}
Ø  Ping                {ISP2}     {Check the connectivity}

Ø  R1(config)#ip sla 1                                                         {1:- SLA entry Number}
Ø  R1(config-ip-sla)#icmp-echo           {ISP1 ip address}
Ø  R1(config-ip-sla-echo)#timeout 200                      {milliseconds}
Ø  R1(config-ip-sla-echo)#frequency 1                       {Second}
Ø  R1(config-ip-sla-echo)#threshold 300                   {milliseconds}
Ø  R1(config-ip-sla-echo)#exit
ü What is IP address we wana ping
ü  icmp-echo: - Using Ping
ü  Timeout:-how long we wana wait for Ping response back {or consider ping lost}
ü  Frequency:-how many seconds we sending the ping
ü  Threshold:-how long until we consider that device down
2nd Step:- Now Start the SLA
Ø  R1(config)#ip sla schedule 1 start-time now life forever
ü  1:-SLA entry number
3rd Step: - To Make Routing Decision Respond to the SLA {entry or probe}
Ø  R1(config)#track 1 rtr 1
Ø  R1(config-track)#exit
ü  1:-Track Object number
ü  rtr:- Response Time Reporter (RTR) Previous name of IP-SLA
ü  1:- entry number

Track object take the SLA entry and essentially says the ip address/interface is up or down
4th Step:- Now attach the Track object to our Static routes
Ø  R1(config)#ip route track 1     
ü  Primary Routes from ISP1
ü  Track 1:- Track object number

Ø  R1(config)#ip route 10       
ü  10 :- Administrative distance      
ü  Backup Route from ISP2
Troubleshooting & Verification Commands:-
Ø  R1#show ip sla statistics
Ø  R1#show track
Ø  R1#show ip route
Now Test
Ø  Shutdown the ISP1 serial interface
Ø  Automatically all the traffic goes to ISP2
After no shut

Ø  And all traffic goes to ISP

Click Here To Download The PDF File

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