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Implementation of ROAS (Router-On-A-Stick) for inter VLANs communicati

siskum
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Implementation of ROAS (Router-On-A-Stick) for inter VLANs communication in L2 Switches
with Network Redundancy at Remote Area Smaller Network with Internet Access
========================================================================

ROAS is best suitable for smaller networks at remote area, SVI(Switch Vertual Interface),
Switch Roted Port and EtherChannels are most suitable for large area network.

Differences are:
-ROAS uses VLAN uniq id numbers in Router's subinterfaces with IP address to egress/ingress data packet/frame,
-SVI uses each VLAN as a interface with IP address, one of VLAN interface act to egress/ingress data packet/frame,
-Switch Routed Port - in the switch one port act similler to Router port (no VLAN involvement) to egress/ingress data packet/frame,
-EtherChannels are pair of Point-to-point links connected between two switches. Port-channel/channel-group number act as interface to egress/ingress data packet/frame.

Here I implement ROAS in L2 Switches connected to two Routers with redundancy of Mesh Network topology.
Head office and three Brach offices connect to Mesh topology for network redundancy.

VLAN 10- Admin
VLAN 20- Sales
VLAN 30- Finance
VLAN 40- Operation

Switches
=========
1. Core-SW1 - Head Office
2. BOA-SW2 - Branch office A
3. BOB-SW3 - Branch office B
4. BOC-SW4 - Branch office C

Each brach office exists all VLANs-10,20,30,40

ROAS-VLANs-L2SW-RedundancyROAS-VLANs-L2SW-Redundancy

Each Switch (Core-SW1,BOA-SW2,BOB-SW3,BOC-SW4) have to Configure with same VLAN numbers.
==================================================================================
1. Create VLANs

Switch>enable
Switch#config t
Switch(config)#vlan 10
Switch(config-vlan)#name Admin
Switch(config-vlan)#vlan 20
Switch(config-vlan)#name Sales
Switch(config-vlan)#vlan 30
Switch(config-vlan)#name Finance
Switch(config-vlan)#vlan 40
Switch(config-vlan)#name Operation
Switch(config-vlan)#exit
Switch(config)#

2. Assigning Trunk mode and VLANs for Core-SW1 switchports.

Switch(config)#
Switch(config)#int rang g0/1
Switch(config-if-range)#switchport mode trunk
Switch(config-if-range)#no shut
Switch(config-if-range)#int rang f0/1-5
Switch(config-if-range)#switchport mode trunk
Switch(config-if-range)#no shut
Switch(config-if-range)#int rang f0/6-10
Switch(config-if-range)#switchport mode access
Switch(config-if-range)#switchport access vlan 10
Switch(config-if-range)#no shut
Switch(config-if-range)#int rang f0/11-15
Switch(config-if-range)#switchport mode access
Switch(config-if-range)#switchport access vlan 20
Switch(config-if-range)#no shut
Switch(config-if-range)#int rang f0/16-20
Switch(config-if-range)#switchport mode access
Switch(config-if-range)#switchport access vlan 30
Switch(config-if-range)#no shut
Switch(config-if-range)#int rang f0/21-24
Switch(config-if-range)#switchport mode access
Switch(config-if-range)#switchport access vlan 40
Switch(config-if-range)#no shut
Switch(config-if-range)#exit
Switch(config)#

3. Assigning trunk mode and VLANs to rest of the each Switch(BOA-SW2,BOB-SW3,BOC-SW4)Switchports

Switch(config)#
Switch(config)#int rang g0/2
Switch(config-if-range)#switchport mode trunk
Switch(config-if-range)#no shut
Switch(config)#
Switch(config)#int rang f0/1-6
Switch(config-if-range)#switchport mode access
Switch(config-if-range)#switchport access vlan 10
Switch(config-if-range)#no shut
Switch(config-if-range)#int rang f0/7-12
Switch(config-if-range)#switchport mode access
Switch(config-if-range)#switchport access vlan 20
Switch(config-if-range)#no shut
Switch(config-if-range)#int rang f0/13-18
Switch(config-if-range)#switchport mode access
Switch(config-if-range)#switchport access vlan 30
Switch(config-if-range)#no shut
Switch(config-if-range)#int rang f0/19-24
Switch(config-if-range)#switchport mode access
Switch(config-if-range)#switchport access vlan 40
Switch(config-if-range)#no shut
Switch(config-if-range)#exit
Switch(config)#


Configuration of Routers (ROAS1 and ROAS2)
===========================================

1. Create DHCP Pool Net in both routers (ROAS1 & ROAS2) for each VLANs client machines (IP address assignment will take automatically for each client machine in all VLANs)

ROAS1#conf t
ROAS1(config)#
ROAS1(config)#ip dhcp excluded-address 10.40.4.1 10.40.4.4
ROAS1(config)#ip dhcp excluded-address 10.30.3.1 10.30.3.4
ROAS1(config)#ip dhcp excluded-address 10.20.2.1 10.20.2.4
ROAS1(config)#ip dhcp excluded-address 10.10.1.1 10.10.1.4
ROAS1(config)#
ROAS1(config)#ip dhcp pool Net10
ROAS1(dhcp-config)# network 10.10.1.0 255.255.255.0
ROAS1(dhcp-config)# default-router 10.10.1.1
ROAS1(dhcp-config)#ip dhcp pool Net20
ROAS1(dhcp-config)# network 10.20.2.0 255.255.255.0
ROAS1(dhcp-config)# default-router 10.20.2.1
ROAS1(dhcp-config)#ip dhcp pool Net30
ROAS1(dhcp-config)# network 10.30.3.0 255.255.255.0
ROAS1(dhcp-config)# default-router 10.30.3.1
ROAS1(dhcp-config)#ip dhcp pool Net40
ROAS1(dhcp-config)# network 10.40.4.0 255.255.255.0
ROAS1(dhcp-config)# default-router 10.40.4.1
ROAS1(dhcp-config)#exit
ROAS1(config)#

2. ROAS1 Configuration.
Create sub-interfaces, assigned VLAN uniq ID and IP address for sub-interfaces in ROAS1
-----------------------------------------------------------------------------------------
In the ROAS1 router G0/0 interface

ROAS1(config)#
ROAS1(config)#interface GigabitEthernet0/0
ROAS1(config-if)# no ip address
ROAS1(config-if)# ip nat inside
ROAS1(config-if)# no shutdown
ROAS1(config-if)#
ROAS1(config-if)#interface GigabitEthernet0/0.10
ROAS1(config-subif)# encapsulation dot1Q 10
ROAS1(config-subif)# ip address 10.10.1.1 255.255.255.0
ROAS1(config-subif)#
ROAS1(config-subif)#interface GigabitEthernet0/0.20
ROAS1(config-subif)# encapsulation dot1Q 20
ROAS1(config-subif)# ip address 10.20.2.1 255.255.255.0
ROAS1(config-subif)#
ROAS1(config-subif)#interface GigabitEthernet0/0.30
ROAS1(config-subif)# encapsulation dot1Q 30
ROAS1(config-subif)# ip address 10.30.3.1 255.255.255.0
ROAS1(config-subif)#
ROAS1(config-subif)#interface GigabitEthernet0/0.40
ROAS1(config-subif)# encapsulation dot1Q 40
ROAS1(config-subif)# ip address 10.40.4.1 255.255.255.0
ROAS1(config-subif)#exit
ROAS1(config)#

In the ROAS1 router G0/1 interface assigned an IP address to egress/ingress packet/frame to Internet access ISP router
ROAS1(config)#
ROAS1(config)#interface GigabitEthernet0/1
ROAS1(config-if)# ip address 192.168.9.1 255.255.255.252
ROAS1(config-if)# ip nat outside
ROAS1(config-if)# no shutdown
ROAS1(config-if)#
ROAS1(config-if)#
ROAS1(config-if)#interface Vlan1
ROAS1(config-if)# no ip address
ROAS1(config-if)# shutdown
ROAS1(config-if)#exit
ROAS1(config)#

Internal all trafic forward to Internet access ISP router
ROAS1(config)#
ROAS1(config)#ip route 0.0.0.0 0.0.0.0 192.168.9.2
ROAS1(config)#

3. ROAS2 Configuration.
Create sub-interfaces, assigned VLAN uniq ID and IP address for sub-interfaces in ROAS2
-------------------------------------------------------------------------------
ROAS2#conf t
ROAS2(config)#
ROAS2(config)#interface GigabitEthernet0/0/0
ROAS2(config-if)# no ip address
ROAS2(config-if)# ip nat inside
ROAS2(config-if)#
ROAS2(config-if)#
ROAS2(config-if)#interface GigabitEthernet0/0/0.10
ROAS2(config-subif)# encapsulation dot1Q 10
ROAS2(config-subif)# ip address 10.10.1.1 255.255.255.0
ROAS2(config-subif)#
ROAS2(config-subif)#interface GigabitEthernet0/0/0.30
ROAS2(config-subif)# encapsulation dot1Q 30
ROAS2(config-subif)# ip address 10.30.3.1 255.255.255.0
ROAS2(config-subif)#exit
ROAS2(config)#
ROAS2(config)#interface GigabitEthernet0/0/1
ROAS2(config-if)# no ip address
ROAS2(config-if)# ip nat inside
ROAS2(config-if)#
ROAS2(config-if)#interface GigabitEthernet0/0/1.20
ROAS2(config-subif)# encapsulation dot1Q 20
ROAS2(config-subif)# ip address 10.20.2.1 255.255.255.0
ROAS2(config-subif)#
ROAS2(config-subif)#interface GigabitEthernet0/0/1.40
ROAS2(config-subif)# encapsulation dot1Q 40
ROAS2(config-subif)# ip address 10.40.4.1 255.255.255.0
ROAS2(config-subif)#exit
ROAS2(config)#

In the ROAS2 router G0/0/2 interface assigned an IP address to egress/ingress packet/frame to Internet access ISP router
ROAS2(config)#
ROAS2(config)#interface GigabitEthernet0/0/2
ROAS2(config-if)# ip address 192.168.9.5 255.255.255.252
ROAS2(config-if)# ip nat outside
ROAS2(config-if)# no shutdown
ROAS2(config-if)# exit
ROAS2(config)#

Internal all trafic forward to Internet access ISP router
ROAS2(config)#
ROAS2(config)#ip route 0.0.0.0 0.0.0.0 192.168.9.6
ROAS2(config)#


4. Internet-R1 router configuration
---------------------------------------
Internet-R1#config t
Internet-R1(config)#
Internet-R1(config)#interface GigabitEthernet0/0/0
Internet-R1(config-if)# ip address 192.168.9.2 255.255.255.252
Internet-R1(config-if)# ip nat inside
Internet-R1(config-if)#
Internet-R1(config-if)#
Internet-R1(config-if)#interface GigabitEthernet0/0/1
Internet-R1(config-if)# ip address 192.168.9.6 255.255.255.252
Internet-R1(config-if)# ip nat inside
Internet-R1(config-if)#
Internet-R1(config-if)#
Internet-R1(config-if)#interface Vlan1
Internet-R1(config-if)# no ip address
Internet-R1(config-if)# shutdown
Internet-R1(config-if)#exit
Internet-R1(config)#

Internal all trafic allows to Internet access ISP router
Internet-R1(config)#
Internet-R1(config-if)#ip route 0.0.0.0 0.0.0.0 192.168.9.5
Internet-R1(config)#ip route 0.0.0.0 0.0.0.0 192.168.9.1
Internet-R1(config)#

 

 

Sisira
3 Replies 3

Martin L
VIP
VIP

Thanks for sharing; if possible attach PT file here (must be zipped); thanks !!!

Hello Martin,

Do you mean Project File (PT) of this implementation that you want ?

This is a solution for all who wants to implement ROAS-inter Vlan communication to do correct implementation with redundancy.

Best regards/Mallawar

Sisira

Yes, if you already have one made; if not, we can make its own.

Thanks