Shulou(Shulou.com)06/02 Report--

OSI package Transport Decapsulation 1-physical layer: responsible for the formulation of the physical and electrical characteristics of the equipment 2-data link layer: Ethernet, PPP, HDLC, ATM, Frame-relay3- network layer: addressing + routing 4-transport layer: TCP + UDP 567 network cable PC-1 = PC-2 ping x.x.x.x transmission distance: repeater hub-signal collision bridge switch-unable to isolate broadcast domain VLAN-same Communication of the same VLAN members on the switch -Communication of the same VLAN members on different switches & access & trunk-ISL-802.1q SMAC-TAG-TYPE 4Byte-vlan- Id: 12bit Between 4096VLAN: route-Gateway & Router & Multilayer switch # physical Interface # Virtual Interface-SVI-routing Table show ip route Display ip routing-table type prefix/mask [ad/metric] via next-hop Interface C 192.168.1.0/24 0/0 is directely connected fas0/0 S 192.168.2.0/24 1/0 via 192.168.1.2 Classification of fas0/1 routing protocols: C non-C static dynamic IGP DV RIP (1) [split horizon / maximum hop] IGRP [number of increased maximum hops / redefined method for calculating metric] bandwidth, delay, reliability, Payload, MTU max transmit unit EIGRP private protocol The algorithm used is Cisco's own: DUAL extension update algorithm LS (SPF-shortest path first, shortest path first) ISIS-CLNP (scalable)-> integrated ISIS OSPFv2/3-IPv4/6 EGP

=

OSPF (SPF) belongs to the link-state routing protocol and is a public standard, which theoretically has no limit on the size of the network. It supports the hierarchical design of the network and divides the network into two layers. Layers are distinguished by the concept of "region". -backbone area-all non-backbone areas must be directly connected to the backbone area in order to communicate normally. Routers are also divided into different types because of the existence of areas:-backbone routers where all links belong to backbone areas;-non-backbone routers where all links belong to non-backbone areas;-area boundary routers (*) [ABR:area border router] must be connected to both backbone and non-backbone areas. -Autonomous system boundary router [ASBR:] A router that has the ability to introduce external routing is called OSPF's ASBR.

-how it works

1. Establish a neighbor table

Use only hello messages.

OSPF routing, switching only between OSPF neighbor routers

Neighbor status: down init 2way Exstart (exchange start) exchange loading full 2, synchronous database LSA-link state advertisement, link-state advertisement 3. Calculate the routing table (calculate the LSA through the SPF algorithm to get the final route entry)-OSPF message: hello: dbd:database description, database description message; lsu:link state update, link-state update message; lsr:link state request, link-state request message; lsack:link state ack, link-state acknowledgement message -OSPF related commands: 0. Establish test port: [R1] interface loopback0 [R1-loopback0] ip address 10.10.1.1 255.255.255.0 [R2] interface loopback0 [R2-loopback0] ip address 10.10.2.2 255.255.255.0 1, configure OSPF [R1] ospf [process-id] / / if not written, the default is 1 [R1-ospf-1] area 0 / / enters area 0; [R1-ospf-1-area-0.0.0.0] network 192.168.12.1 0.0.0.0 / / precisely declares that the link where 192.168.12.1 is located enters OSPF area 0 Then gi0/0/0, enable OSPF 1: # can send packets of ospf 1; # can receive packets of ospf 1 # you can put the network portion of the IP address of the port into the packet of OSPF 1, transmit it out, and give it to the neighboring router. 2. Verify display ospf [1] peer brief / / View brief information of OSPF neighbor table; display ospf [1] peer / / View details of OSPF neighbor table; display ospf [1] brief / / View information about OSPF 1 on local devices; display ip routing-table / / View OSPF routes in the routing table (determine route types and attributes)

=

Factors affecting the establishment of OSPF neighbors: 1. Ensure that the links in the minimum range are Ping to each other; (switch) R1:Ping R2; R2:Ping R1; 2. Ensure that the device port can send messages; # network to declare the correct network range # make sure that the port that receives OSPF messages cannot be "passive port-silent-interface" (the silent-interface of OSPF on Huawei devices can neither send nor receive packets) ospf 1 silent-interface gi0/0/0 3, ensure that the device port can receive messages; # network to declare the correct network range; # make sure that ACL allows OSPF traffic # make sure that the port that receives OSPF messages cannot be "passive port-silent-interface" (the silent-interface of OSPF on Huawei devices, which can neither be sent R1: acl name Deny-OSPF advance rule 5 deny ospf source 192.168.12.2 0.0.0.0 destination 224.0.0.5 0.0.0.0 interface gi0/0/0 traffic-filter inbound acl name Deny-OSPF4, ensure that the key parameters in the OSPF Hello package are consistent [compare parameters in hello] # the RID of a router that directly establishes a neighbor relationship must not be the same; [R1] ospf 1 router-id x.x.x.x / / specify RID reset ospf 1 process / / restart OSPF 1 used by OSPF 1 to take effect; # area ID must be the same [R1] ospf 1 [R1-OSPF-1] area 0 [R1-OSPF-1-area-0.0.0.0] undo network 192.168.12.1 0.0.0.0 [R1-OSPF-1] undo area 0 [R1-OSPF-1] area 1 [R1-OSPF-1-area-1] network 192.168.12.1 0.0.0 .0 # Certification must be successful # subnet mask must be the same (in special cases) # hello time, must be the same; [R1] interface gi0/0/0 [R1-gi0/0/0] ospf timer hello 20 / / when changing hello, the multiple relationship between dead following change is 4 times; # dead time, must also be the same [R1] interface gi0/0/0 [R1-gi0/0/0] ospf timer dead 41 / / when changing dead, hello remains the same; # special tag bits, must be exactly the same; # DR priority, not all 0; (in special cases) [R1] interface gi0/0/0 [R1-gi0/0/0] ospf dr-priority 0 # 3 layer MTU, must be exactly the same Verification command: display ospf peer brief / / View OSPF's neighbor table display ospf interface gi0/0/0 / / View OSPF's interface; Note: ACL has no effect on the traffic initiated by the device itself. ACL has an effect on the traversing traffic of the device.

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.