Cisco Frame Relay horizontal split

Current location:Kubernetes> route switching> Cisco technology> horizontal frame relay splittingTime:Source:UnknownAuthor:AdminClick:126 horizontal split issues on Frame Relay! The topology topoly1 is shown in the figure. In the figure, there is PVC between R1 and R2, R1 and R3, and there is no PVC between R2 and R3. configure the RiP routing protocol on R1, R2, and R3. For example, enable horizontal segmentation on the S0/0 excuse of R1, the route update will be faulty. R3 broadcasts the 192.168.1.0/24 route to R1 through the frame relay link. This will be available in the R1 route table.

650) this. width = 650; "src =" 51cto.com/uploads/allianz 111026/1503134626-0.jpg "/>

Horizontal Split on Frame Relay! The topology topoly1 is shown in the figure. In the figure, there is PVC between R1 and R2, R1 and R3, and there is no PVC between R2 and R3. configure the RiP routing protocol on R1, R2, and R3. For example, enable horizontal segmentation on the S0/0 excuse of R1, route updates may cause problems. R3 broadcasts the 192.168.1.0/24 route to R1 over the frame relay link. This route will be available in the R1 route table. However, due to horizontal segmentation, r1 does not broadcast the route from S0/0. as a result, R2 does not have a route of 192.168.1.0/24. Similarly, R1 will have a route of 172.16.0.0/16, while R3 does not have a route of 172.16.0.0/16.
There are several ways to solve this problem:
1. The first method is to turn off the horizontal split on R1. In fact, if the frame relay is encapsulated in S0/0, the CISCO router will disable the horizontal split by default!
The command to manually disable horizontal segmentation is:
Router (config) # int S0/0
Router (config-if) # no ip split-horizon

2. the second method to solve horizontal split is to add a PVC between R2 and R3, so that R3 will broadcast the route 192.168.1.0/24 to R2 through this PVC, but this will increase the communication fee!

3. The third method uses the subinterface.
The so-called sub-interface is actually a logical interface, and there is no real physical sub-interface. the sub-interface has two types: point-to-point, point-to-point. When the point-to-point interface is used, each sub-interface is used to connect a PVC, the other end of each PVC is connected to a sub-interface or physical interface of the other router. the connection of this seed interface is the same as that of the point-to-point connection through the physical interface. Therefore, the router receives a route broadcast from the sub-interface, route broadcasts are sent from another sub-interface to solve the horizontal split problem!
Point-to-point interface ,. Each pair of point-to-point connections are in different subnets, point-to-point sub-interface configuration,
(1) configure the main interface
Router (config) # int S0/0
Router (config-if) # no ip addrees
Router (config-if) # encapsulation frame-Relay
Router (config-if) # frame-Relay lm-type cisco
Router (config-if) # no frame-Relay inverse-arp
Router (config-if) # no shut
(2) create a point-to-point interface
Router (config) # int S0/0.2 point-to-point
(3) configure the Sub-interface
Router (config-subif) # ip add 12.12.1 255.255.255.0
Router (config-subif) # frame-Relay interface-dlci 102
In the subinterface, you cannot use the frame-Relay map ip command to configure the frame Relay ing. Instead, you can use the frame-Relay interface-dlci command.
(4) Create S0/0.3 sub-interfaces
Router (config) # int S0/0.3 point-to-point
Router (config-subif) # ip add 13.13.13.1 255.255.255.0
Router (config-subif) # frame-Relay interface-dlci 103
Point-to-point multi-point interface
One-to-multiple-point excuse is used to establish multiple PVC connections to multiple sub-interfaces or physical interfaces of the original vro. Therefore, the interfaces that are added to the connection should all be on the same sub-network. By default, point-to-point interfaces are enabled for horizontal split. Point-to-Point Interface Configuration
(1) configure the main interface

Router (config) # int S0/0
Router (config-if) # no ip addrees
Router (config-if) # encapsulation frame-Relay
Router (config-if) # frame-Relay lm-type cisco
Router (config-if) # no frame-Relay inverse-arp
Router (config-if) # no shut
Router (config) # int s0/0.34 point-to-multipoint
Router (config) # ip add 13.13.13.1 255.255.0
Router (config) # frame-relay map ip 13.13.13.3 103 broad
Router (config) # frame-relay map ip 13.13.13.4 104 broadcast
Router (config-subif) # no ip split-borizon
Case column: RIP configuration on Frame Relay
R2 Configuration
(1) Step 1: Enable the Frame Relay switching function.
R2 (config) # frame-Relay switching
(2) Step 1: configure the interface Seal
R2 (config) # int s0/0
R2 (config-if) # no shut
R2 (config-if) # clcok rate 128000
R2 (config-if) # encapsulation frame-Relay
S0/1, S0/2 and S0/0 are slightly the same configuration
(3) Step 3: configure the LMS type.
R2 (config) # int s0/0
R2 (config-if) # frame-Relay lm-type cisco
R2config-if) # frame-Relay intf-type dce
S0/1, S0/2 and S0/0 are the same configuration
(4) Step 4: configure the Frame Relay table
R2 (config) # int s0/0
R2 (config-if) # frame-Relay route 103 interface so0/1 301
R2 (config-if) # frame-Relay route 104 interface so0/2 401
R2 (config) # int s0/1
R2 (config-if) # frame-Relay route 301 interface so0/0 103
R2 (config) # int s0/2
R2config-if) # frame-Relay route 401 interface so0/0 104
R1 Configuration:
R1 (config) # int lo0
R1 (config-if) # no frame-relay inverse-arp
R1 (config-if) # frame-relay map ip 192.168.123.103 broud
R1 (config-if) # frame-relay map ip 192.168.123.4 104 broud
R1 (config-if) # ip add 1.1.1.1 255.255.255.0
R1 (config) # int s0/0
R1 (config-if) # encapsulation frame-Relay
R1 (config-if) # ip add 192.168.123.1 255.255.255.0
R1 (config-if) # frame --- Relay lm-type cisco
R3 and R4 are configured in the same way.
Configure the RIP route protocol:
R1 (config) # router RIP
R1 (config-if) # net 1.0.0.0
R1 (config-if) # net 192.168.1.0
R3 and R4 are configured in the same way.
Check the route table and Test
R3 # sh ip route
R 1.0.0.0/8 [1, 120/1] via 192.168.123.1, s0/1
R 2.0.0/8 [1, 120/1] via 192.168.123.1, s0/1
R 30.0/8 [1, 120/1] via 192.168.123.1, s0/1
R 40.0/8 [1, 120/1] via 192.168.123.1, s0/1

R3 # ping 4.4.4.4
..................
// Here, when ping4.4.4.4, the ICMP packet source IP address is 192.168.123.3 and the target is 4.4.4.4. router R3 query route table that the data packet should be sent to 192.168.123.1, while the Frame Relay ing of 192.168.123.1 is 301, and the data packet to R1, router R1 query route table that the data packet should be sent to 192.168.123.4, the frame relay ing DLCI of 192.168.123.4 is 104. when R4 receives a packet and responds, the source IP address of the ICMP packet changes to 4.4.4.4 and the target IP address changes to 192.168.123.3. R4 has a direct connection route of 192.168.123.0/24, but does not have a frame relay ing of 192.168.123.3, therefore, the issue cannot be blocked. To solve this problem, you can add a R4 ing on R4!
R4 (config) # int so/1
R4 (config-if) # frame-relay map ip 192.168.123.3 401
Similarly, mappings should be added to R3.
R3 (config) # int so/1
R3 (config-if) # frame-relay map ip 192.168.123.4 301