CISCO technology set 3

Ii. PPP
　
PPP (Point-to-Point Protocol) is the successor of SLIP (Serial Line IP protocol). It provides a router-to-router over synchronous and asynchronous circuits) and host-to-network.
CHAP (Challenge Handshake Authentication Protocol) and PAP (Password Authentication Protocol) are generally used to provide security Authentication on PPP encapsulated serial lines. With CHAP and PAP authentication, each vro is identified by its name to prevent unauthorized access.
CHAP and PAP are detailed in RFC 1334.
1. Related commands
Port Settings
Task commands
Set the PPP encapsulation ppp1
Set the authentication method ppp authentication {chap | chap pap | pap chap | pap} [if-needed] [list-name | default] [callin]
Specify the password username password secret
Set the DCE line speed to clockrate speed
Note: 1. To use CHAP/PAP, PPP encapsulation is required. When connecting to a non-Cisco router, PPP encapsulation is generally used. vrouters of other manufacturers generally do not support the Cisco HDLC encapsulation protocol.
2. Example
The S0 ports of router Router1 and Router2 both encapsulate the PPP protocol and adopt CHAP for authentication. In Router1, a user should be created and the peer vro host name should be used as the user name, that is, the user name should be router2. At the same time, a user should be created in Router2, with the peer router host name as the user name, that is, the user name should be router1. The password of the user must be the same.
The settings are as follows:
Router1:
Hostname router1
Username router2 password xxx
Interface Serial0
Ip address 192.200.10.1 255.255.255.0
Clockrate 1000000
Ppp authentication chap
!
Router2:
Hostname router2
Username router1 password xxx
Interface Serial0
Ip address 192.200.10.2 255.255.255.0
Ppp authentication chap
!
　
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Iii. x.25
1. X25 Technology
The X.25 specification corresponds to the OSI Layer 3. The Layer 3 of X.25 describes the grouping format and the packet exchange process. The second layer of X.25 is implemented by LAPB (Link Access Procedure, Balanced). It defines the frame format used for DTE/DCE connections. The first layer of X.25 defines the electrical and physical port features.
X.25 network devices are divided into data terminal devices (DTE), data circuit terminal devices (DCE), and group switching devices (PSE ). DTE is the end system of X.25, such as a terminal, computer, or network host. It is generally located at the user end, and a Cisco router is a DTE device. A dce device is a dedicated communication device, such as a modem and a group switch. PSE is the backbone switch of the public network.
X.25 defines the telephone network for data communication. Each x.25 port assigned to the user has an x.121 address. When the user applies for SVC (switching virtual circuit, when a user at the end of x.25 accesses a user at the other end, the user first calls the peer x.121 address, and then receives or rejects the request at the end of the call, as a result, the connection is established to implement data transmission. When there is no data transmission, the connection is hung up. The entire call process is the same as when we call a common phone. The difference is that x.25 can implement a one-to-multiple-point connection. The x.121 address and htc must all be the same as the parameters assigned by the x.25 service provider. X.25 PVC (permanent virtual circuit), no call process, similar to ddnleased line.
2. Related commands:
Task commands
Set X.25 encapsulation x25 [dce]
Set X.121 address x25 address x.121-address
Set address ing for remote sites x25 map protocol address [protocol2 address2 [... [protocol9 address9] x121-address [option]
Set the maximum number of bidirectional virtual circuits x25 htc citcuit-number1
Set the number of virtual circuits that can be created simultaneously for one connection x25 nvc count2
Set the waiting period before x25 clears idle virtual circuits x25 idle minutes
Restart x25 or clear an svc to start a pvc related parameter clear x25 {serial number | cmns-interface mac-address} [vc-number] 3
Clear x25 virtual circuit clear x25-vc
Show interfaces serial show x25 interface show x25 map show x25 vc
Note: 1. The virtual circuit number ranges from 1 to 4095. The default value of the Cisco router is 1024. Generally, 16 is allocated in China.
2. The virtual circuit count ranges from 1 to 8. The default value is 1.
3. After the related parameters at Layer x.25 are changed, restart x25 using the clear x25 {serial number | cmns-interface mac-address} [vc-number] or clear x25-vc command, otherwise the new parameter may not take effect. At the same time, the relevant parameters of the router should be configured against the service provider's configuration of the x.25 switch port. If the parameters do not match, the connection may fail or other unexpected situations.
3. instance:
3.1. In the following instances, each of the two routers is connected through svc.
The router settings are as follows:
Router1:
Interface Serial0
Encapsulation x25
Ip address 192.200.10.1 255.255.255.0
X25 IP address 110101
X25 htc 16
X25 nvc 2
X25 map ip 192.200.10.2 110102 broadcast
X25 map ip 192.200.10.3 110103 broadcast
!
Router2:
Interface Serial0
Encapsulation x25
Ip address 192.200.10.2 255.255.255.0
X25 IP address 110102
X25 htc 16
X25 nvc 2
X25 map ip 192.200.10.1 110101 broadcast
X25 map ip 192.200.10.3 110103 broadcast
!
Router:
Interface Serial0
Encapsulation x25
Ip address 192.200.10.3 255.255.255.0
X25 IP address 110103
X25 htc 16
X25 nvc 2
X25 map ip 192.200.10.1 110101 broadcast
X25 map ip 192.200.10.2 110102 broadcast
!
Related Debugging commands:
Clear x25-vc
Show interfaces serial
Show x25 map
Show x25 route
Show x25 vc
3.2. in the following instances, router1 and router2 are connected to the router through svc, but router1 and router2 are not directly connected through svc. The serial ports of the three routers run the RIP routing protocol, the sub-interface concept is used. Because of the sub-interface, router1 and router2 both learned the path to access the peer LAN. If you do not use the sub-interface, router1 and router2 will not be able to learn the route to the peer LAN.
A Subinterface is multiple virtual interfaces on a physical interface. It can be used to connect multiple networks on the same physical interface. We know that in order to avoid route loops, the router supports the split horizon rule, which only allows route updates to other interfaces allocated to the router, without allocating route updates to the interfaces received by this route.
In any case, when you use a connection-based interface (like X.25 and Frame Relay) in a WAN environment and the same interface connects multiple remote routers through a virtual circuit (vc, route update information from the same interface cannot be sent back to the same interface, unless separate physical interfaces are forced to connect different routers. Cisco provides subinterfaces as separate interfaces. You can logically connect a vro to different sub-interfaces of the same physical interface, so that route updates from different sub-interfaces can be allocated to other sub-interfaces, and the split horizon rule is also met.
Router1:
Interface Serial0
Encapsulation x25
Ip address 192.200.10.1 255.255.255.0
X25 IP address 110101
X25 htc 16
X25 nvc 2
X25 map ip 192.200.10.3 110103 broadcast
!
Router rip
Network 192.200.10.0
!
Router2:
Interface Serial0
Encapsulation x25
Ip address 192.200.11.2 255.255.255.0
X25 IP address 110102
X25 htc 16
X25 nvc 2
X25 map ip 192.200.11.3 110103 broadcast
!
Router rip
Network 192.200.11.0
!
Router:
Interface Serial0
Encapsulation x25
X25 IP address 110103
X25 htc 16
X25 nvc 2
!
Interface Serial0.1 point-to-point
Ip address 192.200.10.3 255.255.255.0
X25 map ip 192.200.10.1 110101 broadcast
!
Interface Serial0.2 point-to-point
Ip address 192.200.11.3 255.255.255.0
X25 map ip 192.200.11.2 110102 broadcast
!
Router rip
Network 192.200.10.0
Network 192.200.11.0
!
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Frame relay is a high-performance WAN protocol that runs on the physical layer and data link layer of the OSI reference model. It is a data packet exchange technology and a simplified version of X.25. It skips some strong functions of X.25, such as window technology and data re-transmission technology, but relies on high-level protocols to provide error correction, because Frame Relay works on better WAN devices, these devices have more reliable connection services and higher reliability than X.25 WAN devices. They strictly correspond to the Layer 2 of the OSI reference model, while X.25 also provides Layer 3 services, therefore, frame relay has higher performance and more effective transmission efficiency than X.25.
The devices of the frame relay WAN are divided into the data terminal device (DTE) and the data circuit terminal device (DCE), and the Cisco router acts as the DTE device.
Frame Relay technology provides connection-oriented data link layer communication. Each pair of devices has a defined communication link, and the link has a link identifier. This service is implemented through the Frame Relay virtual circuit, and each frame relay virtual circuit identifies itself with a data link identifier (DLCI. The DLCI value is generally specified by the Frame Relay Service Provider. Frame Relay supports both PVC and SVC.
The frame relay Local Management Interface (LMS) is an extension of the basic frame relay standard. It is a signaling standard between the router and the frame relay switch and provides a frame relay management mechanism. It provides many features for managing complex interconnected networks, including global addressing, virtual circuit status messages, and multi-object transmission.
2. Related commands:
Port Settings
Task commands
Set Frame Relay encapsulation frame-relay [ietf] 1
Set Frame-Relay lm-type frame-relay lm-type {ansi | cisco | q933a} 2
Set sub-interface-type interface-number.subinterface-number [multipoint | point-to-point]
Ing protocol address and DLCI frame-relay map protocol-address dlci [broadcast] 3
Set fr dlci No. frame-relay interface-dlci [broadcast]
Note: 1. If a Cisco router is connected to a route Device of another manufacturer, the frame relay Encapsulation Format specified by the Internet Engineering Task Group (IETF) is used.
2. starting from Cisco IOS 11.2, the software supports the local management interface (LMS) "auto-sensing" and "auto-sensing" to enable the interface to determine the type of LMS supported by the switch, you may not explicitly configure the LMS interface type.
3. The broadcast option allows route broadcast information to be transmitted over the Frame Relay Network.
3. Frame Relay point to point configuration instance:
Router1:
Interface serial 0
Encapsulation frame-relay
!
Interface serial 0.1 point-to-point
Ip address 172.16.1.1 255.255.255.0
Frame-reply interface-dlci 105
!
Interface serial 0.2 point-to-point
Ip address 172.16.2.1 255.255.255.0
Frame-reply interface-dlci 102
!
Interface serial 0.3 point-to-point
Ip address 172.16.4.1 255.255.255.0
Frame-reply interface-dlci 104
!
Router2:
Interface serial 0
Encapsulation frame-relay
!
Interface serial 0.1 point-to-point
Ip address 172.16.2.2 255.255.255.0
Frame-reply interface-dlci 201
!
Interface serial 0.2 point-to-point
Ip address 172.16.3.1 255.255.255.0
Frame-reply interface-dlci 203
!
Related Debugging commands:
Show frame-relay LMS
Show frame-relay map
Show frame-relay pvc
Show frame-relay route
Show interfaces serial
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4. Frame Relay Multipoint configuration instance:
Router1:
Interface serial 0
Encapsulation frame-reply
!
Interface serial 0.1 multipoint
Ip address 172.16.1.2 255.255.255.0
Frame-reply map ip 172.16.1.1 201 broadcast
Frame-reply map ip 172.16.1.3 301 broadcast
Frame-reply map ip 172.16.1.4 401 broadcast
!
Router2:
Interface serial 0
Encapsulation frame-reply
!
Interface serial 0.1 multipoint
Ip address 172.16.1.1 255.255.255.0
Frame-reply map ip 172.16.1.2 102 broadcast
Frame-reply map ip 172.16.1.3 102 broadcast
Frame-reply map ip 172.16.1.4 102 broadcast
Article entry: csh responsible editor: csh