[GNS] Frame Relay 실습

Frame Relay

• 기존 WAN에서 전통적으로 사용하던 통신 방식은 X.25
  • 이 방식은 느리고 에러가 많았던 옛날의 WAN 환경에 알맞도록 여러가지 에러 복구 기능 및 흐름 제어 기능이 들어가 있음
  • 프레임 릴레이 방식은 에러 복구와 흐름 제어 등의 데이터 처리 과정을 생략함으로써 보다 효율적인 데이터 전송 방법을 제공
• 프레임 릴레이 용어
  • Data-Link Connection Identifier(DLCI) : 프레임 릴레이 연결을 위한 주소
    • 하나의 인터페이스에 여러 개의 DLCI가 있을 수 있음
  • Local Management Interface(MLI) : DLCI 정보와 함께 설정된 PVC 정보를 알려줌으로써 인터페이스의 다양한 정보와 동작 상태등을 제공하는 기능
    • 라우터에서 MLI를 세팅할 때 LMI 타입을 서로 맞추어야 통신이 가능
• Frame Relay 인캡슐레이션 방식
  • Cisco 방식

Router(config)# interface serial 0   // inter s 0
Router(config-if)# encapsulation frame-relay

• IETF 방식

Router(config)# inter s 0
Router(config-if)# encapsulation frame-relay ietf

• Frame Relay LMI 설정

Router(config)# inter s 0
Router(config-if)# frame-relay lmi-type ?

• LMI는 IOS 버전 11.2 이상부터는 자동으로 세팅하기 때문에 따로 구성할 필요 없음

• 서브 인터페이스 설정

Router(config)# interface serial 0.1   // 인터페이스 뒤에 점을 찍고 서브 번호를 붙임
Router(config)# interface serial 0.1 ?
    multipoint
    point-to-point

• DLCI 연결
  • 프레임 릴레이 구성에서 Encapsulation 타입과 LMI를 잡아주면 Inverse ARP가 동작해서 자동으로 연결
  • 수동으로 연결하기 위해서는 frame-relay interface 나 frame-relay map 명령을 수행
    • 주의 사항은 frame-relay map 명령과 Inverse ARP는 같이 동작하지 않음
    • Inverse ARP를 사용하는 경우에는 절대로 frame-relay map을 같이 사용하면 안됨
  • 서브 인터페이스 타입이 point-to-point인 경우 frame-relay map 명령이 아닌 frame-relay interface-dlci 명령어 사용
  • 피지컬 인터페이스나 multi-point 서브 인터페이스를 이용해서 프레임 릴레이를 구성하면 frame-relay map 명령어 사용

Frame Relay 예제 - 1

후니의 쉽게 쓴 CISCO 네트워킹 Vol.2 154p

예제 구성

RouterA 구성

RouterA# conf t
RouterA(conf)# inter serial 2/0
RouterA(conf-if)# no shutdown
RouterA(conf-if)# no ip directed-broadcast
RouterA(conf-if)# encapsulation frame-relay
RouterA(conf-if)# frame-relay lmi-type ansi
RouterA(conf)# inter serial 2/0.1 point-to-point
RouterA(conf-subif)# no shutdown
RouterA(conf-subif)# ip address 203.240.15.1 255.255.255.0
RouterA(conf-subif)# frame-relay interface-dlci 102  // point-to-point인 경우 map 명령어 대신 해당 명령어 사용
RouterA(conf)# inter serial 2/0.2 point-to-point
RouterA(conf-subif)# no shutdown
RouterA(conf-subif)# ip address 203.240.20.1 255.255.255.0
RouterA(conf-subif)# frame-relay interface-dlci 103

RouterB 구성

RouterB# conf t
RouterB(conf)# inter serial 2/0
RouterB(conf-if)# no shutdown
RouterB(conf-if)# ip address 203.240.15.2 255.255.255.0
RouterB(conf-if)# encapsulation frame-relay
RouterB(conf-if)# no ip mroute-cache
RouterB(conf-if)# frame-relay map ip 203.240.15.1 201 broadcast
RouterB(conf-if)# frame-relay lmi-type ansi

RouterC 구성

RouterC# conf t
RouterC(conf)# inter serial 2/0
RouterC(conf-if)# no shutdown
RouterC(conf-if)# ip address 203.240.20.3 255.255.255.0
RouterC(conf-if)# encapsulation frame-relay
RouterC(conf-if)# frame-relay map ip 203.240.20.1 301 broadcast
RouterC(conf-if)# frame-relay lmi-type ansi

Frame Relay Switch 구성

FR-SW# conf t
FR-SW(conf)# frame-relay switching   // 자신이 프레임 릴레이 스위치의 역할을 수행
FR-SW(conf)# inter serial 2/0
FR-SW(conf-if)# no shutdown
FR-SW(conf-if)# encapsulation frame-relay
FR-SW(conf-if)# clock rate threshold 2000000
FR-SW(conf-if)# frame-relay lmi-type ansi
FR-SW(conf-if)# frame-relay intf-type dce
FR-SW(conf-if)# frame-relay route 102 interface Serial2/1 201
FR-SW(conf-if)# frame-relay route 103 interface Serial2/2 301
FR-SW(conf)# inter serial 2/1
FR-SW(conf-if)# no shutdown
FR-SW(conf-if)# encapsulation frame-relay
FR-SW(conf-if)# clock rate threshold 2000000
FR-SW(conf-if)# frame-relay lmi-type ansi
FR-SW(conf-if)# frame-relay intf-type dce
FR-SW(conf-if)# frame-relay route 201 interface Serial2/0 102
FR-SW(conf)# inter serial 2/2
FR-SW(conf-if)# no shutdown
FR-SW(conf-if)# encapsulation frame-relay
FR-SW(conf-if)# clock rate threshold 2000000
FR-SW(conf-if)# frame-relay lmi-type ansi
FR-SW(conf-if)# frame-relay intf-type dce
FR-SW(conf-if)# frame-relay route 301 interface Serial2/0 103

프레임 릴레이 검증

• show frame-relay pvc

• show frame-relay map

Frame Relay 예제 - 2

후니의 쉽게 쓴 CISCO 네트워킹 Vol.2 160p

예제 구성

• 예제 1과 다르게 RouterA-RouterB와 RouterA-RouterC이 같은 네트워크 대역

RouterA 설정

RouterA# conf t
RouterA(conf)# inter serial 2/0
RouterA(conf-if)# no shutdown
RouterA(conf-if)# encapsulation frame-relay
RouterA(conf-if)# frame-relay lmi-type ansi
RouterA(conf)# inter serial 2/0.1 multipoint    // 두 개가 같은 ip 대역이기 때문에 multipoint
RouterA(conf-subif)# no shutdown
RouterA(conf-subif)# ip address 203.240.15.1 255.255.255.0     // sub interface에 ip 설정
RouterA(conf-subif)# frame-relay map 203.240.15.2 102 broadcast    // map을 이용해 설정
RouterA(conf-subif)# frame-relay map 203.240.15.3 103 broadcast

RouterB 설정

RouterB# conf t
RouterB(conf)# inter serial 2/0
RouterB(conf-if)# no shutdown
RouterB(conf-if)# ip address 203.240.15.2 255.255.255.0
RouterB(conf-if)# encapsulation frame-relay
RouterB(conf-if)# frame-relay lmi-type ansi
RouterB(conf-if)# frmae-relay map ip 203.240.15.1 201 broadcast
RouterB(conf-if)# frame-relay map ip 203.240.15.3 201 broadcast

RouterC 설정

RouterC# conf t
RouterC(conf)# inter serial 2/0
RouterC(conf-if)# no shutdown
RouterC(conf-if)# ip address 203.240.15.3 255.255.255.0
RouterC(conf-if)# encapsulation frame-relay
RouterC(conf-if)# frame-relay lmi-type ansi
RouterC(conf-if)# frmae-relay map ip 203.240.15.1 301 broadcast
RouterC(conf-if)# frmae-relay map ip 203.240.15.2 301 broadcast

Frame Relay Switch 설정

FR-SW# conf t
FR-SW(conf)# frmae-relay switching
FR-SW(conf)# inter serial 2/0
FR-SW(conf-if)# no shutdown
FR-SW(conf-if)# clock rate threshold 2000000
FR-SW(conf-if)# encapsulation frame-relay
FR-SW(conf-if)# frame-relay lmi-type ansi
FR-SW(conf-if)# frame-relay intf-type dce
FR-SW(conf-if)# frame-relay route 102 interface Serial2/1 201
FR-SW(conf-if)# frame-relay route 103 interface Serial2/2 301
FR-SW(conf)# inter serial 2/1
FR-SW(conf-if)# no shutdown
FR-SW(conf-if)# clock rate threshold 2000000
FR-SW(conf-if)# encapsulation frmae-relay
FR-SW(conf-if)# frame-relay lmi-type ansi
FR-SW(conf-if)# frame-relay intf-type dce
FR-SW(conf-if)# frame-relay route 201 interface Serial2/0 102
FR-SW(conf)# inter serial 2/2
FR-SW(conf-if)# no shutdown
FR-SW(conf-if)# clock rate threshold 2000000
FR-SW(conf-if)# encapsulation frame-relay
FR-SW(conf-if)# frame-relay lmi-type ansi
FR-SW(conf-if)# frame-relay intf-type dce
FR-SW(conf-if)# frame-relay route 301 interface Serial2/0 103

프레임 릴레이 검증

• show frame-relay map

연결 확인

• RouterB -> RouterA

• RouterB -> RouterC