Monday, December 31, 2012

Combining Etherchannel With Router On A Stick - When Two Evils Meet

It all started of as a thought in mind to write a new blog post on topic which I personally feel that no one talked about earlier or even any CCIE Lab Workbooks covered. But after some time my situation was like:





Okay, I'll talk about that later. First lets get started with what we are going to learn new today. The idea in mind was to combine two Evils together. 




Usually CCNA, CCNP & Evil CCIEs are familiar with these topics individually:

1. Router On A Stick
2. Ether-Channel

But what I thought was to combine these two together and come up with a new solution as -  Router On A Stick With Ether-Channel, Which will look something like :-)




Now after enough fun let's get into details:

 Physical Topology

Logical Topology



Now before we move ahead, for those which are not familiar with these two topics (Ether-Channel & Router On A Stick), I would recommend following Pre readings :

http://www.thebryantadvantage.com/CCNA640802CCENTRouterOnAStick.htm


http://www.thebryantadvantage.com/CCNA640802CCENTRouterOnAStickConfiguration.htm

http://www.thebryantadvantage.com/CCNA640802CCENTRouterOnAStickTroubleshooting.htm

http://blog.ipexpert.com/2009/12/23/explaining-etherchannel/

http://www.cisco.com/en/US/tech/tk389/tk213/technologies_white_paper09186a0080092944.shtml

http://www.cisco.com/en/US/tech/tk389/tk213/technologies_tech_note09186a0080094714.shtml


Now lets move to Cli where I am going to show everything into 2 Important Steps:

1. Configuration
2. Verification


BTW,  I used a Cisco 3725 Router with 16 Port Switching Module to emulate the Switch part here so some of verification and configuration commands are specific to this setup as here Router is acting as a Switch.


SWITCH
======



SW#vlan database
SW(vlan)#vlan 10
VLAN 10 added:
    Name: VLAN0010

SW(vlan)#vlan 20
VLAN 20 added:
    Name: VLAN0020

SW(vlan)#apply
APPLY completed.
SW(vlan)#exit
APPLY completed.
Exiting....


SW#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
SW(config)#int f1/3
SW(config-if)#switchport mode access
SW(config-if)#switchport access vlan 10
SW(config-if)#spanning-tree portfast < Optional
%Warning: portfast should only be enabled on ports connected to a single host.
 Connecting hubs, concentrators, switches,  bridges, etc.to this interface
 when portfast is enabled, can cause temporary spanning tree loops.
 Use with CAUTION

%Portfast has been configured on FastEthernet1/3 but will only
 have effect when the interface is in a non-trunking mode.
SW(config-if)#exit

SW(config)#int f1/4
SW(config-if)#switchport mode access
SW(config-if)#switchport access vlan 20
SW(config-if)#spanning-tree portfast < Optional
%Warning: portfast should only be enabled on ports connected to a single host.
 Connecting hubs, concentrators, switches,  bridges, etc.to this interface
 when portfast is enabled, can cause temporary spanning tree loops.
 Use with CAUTION

%Portfast has been configured on FastEthernet1/3 but will only
 have effect when the interface is in a non-trunking mode.
SW(config-if)#exit


SW(config)#interface range f1/0 - 1
SW(config-if-range)#channel-group 1 mode on
SW(config-if-range)#exit
SW(config)#

SW(config)#interface port-channel 1 < All Trunk Config Goes To Port-Channel
SW(config-if)#switchport trunk encapsulation dot1q
SW(config-if)#switchport mode trunk
SW(config-if)#exit


R1
==


R1(config)#int port-channel 1 < Lets first Create Port-Channel Interface
R1(config-if)#exit


R1(config)#interface range f0/0 - 1
R1(config-if-range)#channel-group 1
%Interface MTU set to channel-group MTU 1500.

%Interface MTU set to channel-group MTU 1500.

R1(config-if-range)#no shut
R1(config-if-range)#exit


R1(config)#int port-channel 1.10 < Create Port-Channel Sub-interface for VLAN 10
R1(config-subif)#encapsulation dot1Q 10
R1(config-subif)#ip add 10.0.0.254 255.255.255.0
R1(config-subif)#no shut
R1(config-subif)#exit


R1(config)#int port-channel 1.20 < Create Port-Channel Sub-interface for VLAN 20

R1(config-subif)#encapsulation dot1Q 20
R1(config-subif)#ip add 20.0.0.254 255.255.255.0
R1(config-subif)#no shut
R1(config-subif)#end


Verification:
========


R1#sh ip int brief | exclude down
Interface              IP-Address      OK? Method Status                Protocol
FastEthernet0/0        unassigned      YES unset  up                    up
FastEthernet0/1        unassigned      YES unset  up                    up
Port-channel1          unassigned      YES unset  up                    up
Port-channel1.10       10.0.0.254      YES manual up                    up
Port-channel1.20       20.0.0.254      YES manual up                    up



SW#sh vlan-switch brief | include _10_|_20_
10   VLAN0010                         active    Fa1/3
20   VLAN0020                         active    Fa1/4



SW#sh interface trunk

Port      Mode         Encapsulation  Status        Native vlan
Po1       on           802.1q         trunking      1

Port      Vlans allowed on trunk
Po1       1-1005

Port      Vlans allowed and active in management domain
Po1       1,10,20

Port      Vlans in spanning tree forwarding state and not pruned
Po1       1,10,20



SW#sh spanning-tree vlan 10 | include forwarding
 Port 44 (FastEthernet1/3) of VLAN10 is forwarding
   Number of transitions to forwarding state: 1
 Port 321 (Port-channel1) of VLAN10 is forwarding
   Number of transitions to forwarding state: 1
SW#
SW#sh spanning-tree vlan 20 | include forwarding
 Port 45 (FastEthernet1/4) of VLAN20 is forwarding
   Number of transitions to forwarding state: 1
 Port 321 (Port-channel1) of VLAN20 is forwarding
   Number of transitions to forwarding state: 1


SW#sh etherchannel summary | b Group
Group Port-channel  Ports
-----+------------+-----------------------------------------------------------
1     Po1(SU)     Fa1/0(P)   Fa1/1(P)



HOST-A#sh ip int b | exclude unassignd|down
Interface                  IP-Address      OK? Method Status                Protocol
FastEthernet0/0            10.0.0.3        YES manual up                    up


HOST-A#ping 20.0.0.4

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 20.0.0.4, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 16/34/68 ms



HOST-B#sh ip int brief | e una|do
Interface                  IP-Address      OK? Method Status                Protocol
FastEthernet0/0            20.0.0.4        YES manual up                    up


HOST-B#ping 10.0.0.3

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.0.0.3, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 16/30/72 ms


R1#sh ip arp
Protocol  Address          Age (min)  Hardware Addr   Type   Interface
Internet  10.0.0.3                2   c416.1064.0000  ARPA   Port-channel1.10
Internet  10.0.0.254              -   ca14.1c58.0008  ARPA   Port-channel1.10
Internet  20.0.0.4                2   c417.1064.0000  ARPA   Port-channel1.20
Internet  20.0.0.254              -   ca14.1c58.0008  ARPA   Port-channel1.20


R1#sh ip route | b ^G
Gateway of last resort is not set

      10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C        10.0.0.0/24 is directly connected, Port-channel1.10
L        10.0.0.254/32 is directly connected, Port-channel1.10
      20.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C        20.0.0.0/24 is directly connected, Port-channel1.20
L        20.0.0.254/32 is directly connected, Port-channel1.20



SW#sh mac-address-table dynamic
Non-static Address Table:
Destination Address  Address Type  VLAN  Destination Port
-------------------  ------------  ----  --------------------
ca14.1c58.0008          Dynamic       1     Po1
c416.1064.0000          Dynamic      10     FastEthernet1/3
c417.1064.0000          Dynamic      20     FastEthernet1/4


HOST-A#sh int f0/0 | i bia
  Hardware is Gt96k FE, address is c416.1064.0000 (bia c416.1064.0000)


HOST-B#sh int f0/0 | i bia
  Hardware is Gt96k FE, address is c417.1064.0000 (bia c417.1064.0000)


R1#sh int f0/0 | i bia
  Hardware is i82543 (Livengood), address is ca14.1c58.0008 (bia ca14.1c58.0008)


R1#sh int f0/1 | i bia
  Hardware is i82543 (Livengood), address is ca14.1c58.0008 (bia ca14.1c58.0006)


R1#sh int Po1 | i bia
  Hardware is FEChannel, address is ca14.1c58.0008 (bia 0000.0000.0000)






And of course that thing which made smashing my head against the key-board, Here are the details:


https://learningnetwork.cisco.com/thread/50039?tstart=0


Further Readings:


http://www.cisco.com/en/US/prod/collateral/routers/ps5855/prod_white_paper0900aecd806f698a.pdf

HTH...
Deepak Arora
Evil CCIE

1 comment:

Anonymous said...

Very good tutorial. I am trying to apply this to a 3500xl switch since they do not support layer 3 routing. I want to combine the switching capabilities of the 3500xl and add on a router to provide the routing functionalities. This will then be connected to a 3550 svi port channel. Hope to save some money and not buy an extra 3550. This set up may work for me.