The following free lab is available for everyone out there who wants to experiment and test with live Cisco IOS. Few major features as HSRP, EIGRP and Frame-relay (where you can play with "variance" parameter in EIGRP) are preconfigured and established. The lab can help you in your CCNA, CCENT or ICND preparation. You have full access to all devices with user in privilege level 15 so you can make changes and experiment with your own configurations.
Network diagram and Initial configuration
The following is the scheme of the lab. You have direct access to the CONSOLE port on each device. The lab is initialized with some basic configurations which are used after every lab reset that is happening every 8 hours.
In this example we have few L3 redundancy features which can be tested. In example the default gateway for SW1 is an HSRP address. On the other side of the scheme we have R7 with redundant serial connections.
HSRP - By default we have a HSRP configured between R1 and R2. The router R1 should be the active router because he has higher priority. You can check the HSRP status by issuing the following command:
R1#show standby briefP indicates configured to preempt.|Interface Grp Pri P State Active Standby Virtual IPEt0/1 10 200 P Active local 10.1.1.67 10.1.1.65
Of course you can check if the virtual IP address is reachable from the switch SW1. The HSRP address is used as a default gateway on SW1:
SW1#show running-config | include gatewayip default-gateway 10.1.1.65SW1#SW1#ping 10.1.1.65Type escape sequence to abort.Sending 5, 100-byte ICMP Echos to 10.1.1.65, timeout is 2 seconds:!!!!!Success rate is 100 percent (5/5), round-trip min/avg/max = 1/3/8 ms
The other example for redundant connection are the serial links connected to R7. The router is configured to utilize both links although they are with different bandwidth. It is a perfect example for the load sharing capability of the EIGRP:
R7#show running-config...!router eigrp 100variance 2network 172.16.0.0!...
R7#show interfaces serial 1/0Serial1/0 is up, line protocol is upHardware is M4TInternet address is 172.16.33.10/30MTU 1500 bytes, BW 1344 Kbit/sec, DLY 20000 usec,...
R7#show interfaces serial 1/1Serial1/1 is up, line protocol is upHardware is M4TInternet address is 172.16.33.14/30MTU 1500 bytes, BW 1544 Kbit/sec, DLY 20000 usec,...
As you can see the difference between both serial links is 200 Kbit/sec. Now, in order to demonstrate the load balancing of the connection you can try to ping switch SW1 from switch SW2:
SW2#ping 10.1.1.71 repeat 100Type escape sequence to abort.Sending 100, 100-byte ICMP Echos to 10.1.1.71, timeout is 2 seconds:!!!!!U.U.U.U.U.U!!!!!!!!!!!!.U.U.U.U.U.!!!!!!!!!!!!U.U.U.U.U.U!!!!!!!!!!!!.U.U.U.U.U.!!!!!!!!!!!!U.USuccess rate is 53 percent (53/100), round-trip min/avg/max = 24/29/32 ms
But why some of the packets are missing? The tricky part is that there is applied access list on router R5 which is blocking the ICMP packets. This is done in order confirm that some of the packets originally sent to SW1 are being transferred through the serial link between R5 and R7.
R5#show running-config...!interface Serial0/1bandwidth 1344ip address 172.16.33.9 255.255.255.252ip access-group NoPing inencapsulation pppserial restart-delay 0!...!ip access-list extended NoPingdeny icmp any anypermit ip any any!
By using the variance parameter in the EIGRP configuration R7 is utilizing both serial links but there is one more requirement in order to make this work and this is the ip cef (Cisco Express Forwarding). If this feature is enabled, the router will choose one of the links for one entire session and you will not be able to experience the load balancing. This is why the ip cef option is turned off on the router R7.
In the following table are all devices with their interfaces and IP addresses.
Lab Access and Status
All devices can be accessed via telnet protocol by using the hostname and the ports from the table below. The initial credentials are:
- username: admin
- password: learncisconet
- enable secret: learncisconet
Please, do not change the default credentials.
The following tables contain the current status of the lab.
|Last reset||3h 38m ago|
|Next reset in||4h 21m|