30-04-2011, 02:26 PM
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Inter-vlan routing
CISCO WORLD
Why we are here ???
The Past-….bye-bye
The Present-….Hang on Tight!!
CISCO CCNA Devices
IP Addressing
An IP(Internet Protocol) address is a unique identifier for a node or the host connection on an IP network.
An IP address is a 32 bit binary number usually represented as 4 decimal values , each representing 8 bits, in the range 0 to 255 (known as octets) seprated by decimal points. This is known as “doted decimal” notation. Example: 140.179.220.200
140 .179 .220 .200
10001100.10110011.11011100.11001000
VLAN
Virtual Local Area Network.
Logical grouping of Network users and resources connected to administratively defined ports on a Switch.
Ability to create smaller Broadcast domains within a layer 2 switched internetwork by assigning different Ports on the switch to different sub networks.
Treated like its own Subnet or broadcast domain.
Virtual Trunking Protocol (VTP) is used to update switch databases with VLAN information.
VLAN
Characteristics of the VLAN
Divides the switch into different virtual switches without creating any Physical boundary.
With the help of VLANs we can control the broadcast domain.
Broadcast domain is directly proportional to the number of VLANs created.
VLAN1 is created by default and all the ports are members of the VLAN1 by Default.
Trunking protocols are used to maintain VLANs.
Advantages
Cost and Time Reduction.
Creating Virtual Work Groups.
Increased performance.
Improved manageability.
Network tuning and simplification of software configurations.
Physical topology independence.
Increased security options.
Limitations
Broadcast Limitations.
Device Limitations.
Port Constraints.
Inter-Vlan Routing
It is the connection between two or more VLANs.
The network is established by connecting these two VLANs with the router.
With the help of Inter-VLAN, the stations in a VLAN can now communicate and share resources with the stations of another VLAN.
Routers allow broadcasts to occur only within the originating network, while switches forward broadcasts to all segments.
Need of Inter-VLAN Routing
To reduce the broadcast domain of a switch.
To reduce complexity.
To reduce troubleshooting.
To save switch ports.
To provide the flexibility to the user.
To reduce cost.
Advantages of Inter-VLAN Routing
Better Management
Better Performance
Reduced Complexity
Reduced Cost
Traditional inter-VLAN routing
The router has one physical port for each VLAN.
Each port has an IP address on its own VLAN.
Routing is the same as routing between any subnets.
Traditional inter-VLAN routing
Trunks between switches.
No trunk to router.
No tags on frames to router.
Router on a stick
R1 F0/0 has sub-interfaces, one for each VLAN.
Each has its own IP address.
VLAN tags on trunk.
Availability of trunking
Not all routers allow subinterfaces for VLAN trunking on Ethernet ports.
It depends on the IOS feature set.
Some of ours do, others do not.
VTP Modes
Server:-Create, remove, and modify VLANs.
Client:-Behave the same way as VTP servers, but you cannot create, change, or delete VLANs on the local device.
Transparent:-Switch will not advertise its VLAN configuration and does not synchronize its VLAN configuration based on received messages.
Configuration Commands
Step 1 :-Define the VTP domain name (Case sensitive) .vtp domain name
Step 2 :-Set which VTP version to run.vtp version #
Step 3 :-(Optional) Set a password for the VTP domain. vtp password password
Step 4 :-Verify the VTP configuration. show vtp status
Sub-interfaces
Subinterfaces take the interface name followed by a dot and a number.
It is normal to use the VLAN number. If this ties in with the IP address, even better.
E.g. interface f0/0.10
The subinterfaces each have an IP address.
The physical interface has no IP address.
The physical interfaces needs no shutdown.
Configuring sub-interfaces
R1(config)#interface f0/0.10
R1(config-subif)#encapsulation dot1q 10
R1(config-subif)#ip address 172.17.10.1 255.255.255.0
(add any other subinterfaces)
R1(config-subif)#interface f0/0
R1(config-if)#no shutdown
Sub-interface considerations
Routers have a limited number of interfaces, so subinterfaces help where there are many VLANs.
Subinterfaces share the bandwidth on a physical interface so can cause bottlenecks.
Cheaper to use subinterfaces.
Simpler physical layout but more complex configuration with subinterfaces.
Hardware and Software Requirements
Three Cisco 2950 series Switches.
One Cisco 2600 series Router.
Computers.
Design of network
Intelligence in the network
Increase in desktop computing power.
Introduction of bandwidth-intensive applications.
Expansion of highly sensitive data on the network.
Presence of multiple device types, such as IP phones and LAN access points.
Command Set for the Switches
Switch>
Switch>enable
Switch#configure terminal
Switch (config) #hostname SW-A
SW-A (config) # vtp domain GNDU
SW-A (config) #interface vlan1
SW-A(config)# ip address 70.0.0.25 255.0.0.0
SW-A(config)#no shut
SW-A(config)# int fa0/11 SW-A(config)# switch port mode trunk
SW-A# vlan 10 name MKT
SW-A#exit
SW-A(config)# switchport access vlan 2
Command Set for the router
Router>
Router>enable
Router#configure terminal
Router (config)#hostname RR
RR (config) # interface f0/0
RR(config)# no shut
RR(config)# interface f0/0.1
RR(config)# encapsulation dot1q
RR(config)# ip address 2.0.0.100 255.0.0.0
