Tuesday, March 10, 2015

EIGRP RTP

  • RTP protocol là giao thức reliable dùng để quản lý ,thu nhận EIGRP packet . Realiable delivery có nghĩa rằng phân phát đảm bảo và packet được phân phối đúng thứ tự.
  • Sử dụng 224.0.0.10. mỗi neighbor receiving a reliably multicast packet unicast an ack.
  • Mỗi packet có 2 sequence nummber:
    • Sequence number assigned by the sending router
    • Sequence number incremented by one each time the router send a new packet.
  • Trong một số trường hợp, RTP may use unreliable delivery. No Ack is request, and no sequence number will be included for unreliable delivered EIGRP packet.
  • EIGRP uses multiple packet types, all of which are indentify by protocol number 88 in IP header:
    • Hello sử dụng discovery neighbor and recovery process. Hello packet are multicast and use unreliable delivery.
    • ACK là hello packet với no data. ACK luôn luôn là unicast and use unreliable delivery.
    • Update convey route information. Packet transmitted chỉ khi cần thiết , bao gồm những thông tin cần thiết, và gửi tới router yêu cầu thông tin. Khi update yêu cầu chỉ rõ router, they are unicast. Còn khi yêu cầu bởi multiple routers, such as upon a metric or topology change, they are multicast. Up date always use reliable delivery.
    • Queries and replies are by DUAL finite state machine to manage its diffusing compitation.
      • Queries can be multicast or unicast
      • Replies always unicast
Both they use reliable delivery.
  • Request were type of packet originally intended for use in route servers. This app was nerver implemented, and request packets are noted here only because they are mentioned in some older EIGRP documentation.

  • If any packet is reliably multicast and an ACK is not received from neighbor, the packet will be retransmitted as a unicast to that unresponding neighbor. Nếu ACK không nhận sau 16 time khi unicast retransmit, neighbor wikk be declared dead.

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