Cisco Cisco Summary

Trunk Link Trunk: Same inter-VLAN communication on different switches
How to play tag tag encapsulation
Package Type: IEEE 802.1q/cisco ISL
IEEE 802.1q:4 Bytes, internal encapsulation, public
Cisco isl:30 bytes External encapsulation, private

Switch port configuration mode: Trunk/acces (OFF)/Dynamic desirable/dynamic Auto
Two auto NO mode of operation generally either trunk or access

Ethernet Channel: Multiple physical ports to form a logical port for greater bandwidth

DHCP: Dynamic Host Configuration protocol that automatically assigns network parameters to clients
Three-layer switching---switch from three-layer switch---PC

Three-layer switch:
Two tables: FIB forwarding information table corresponds to three layers
adjacency table corresponds to layer Two
strong> * * * +
Dynamic routing protocol classification:
by algorithm:
Distance vector: RIP/ Igrp/eigrp 15-Hop
link state: Ospf/is-is
by Purpose: IGP Internal Gateway routing protocol as (autonomous system)
EGP--BGP External Gateway Routing protocol Autonomous System with
intra-company if there are two BGP dual-line IP addresses are Independent application, not related to the operator.
RIP: Metric is hop count---Number of routers the maximum hop count is 15 hops
OSPF:
5 packet types: Hello packet----DPD According to the library description message---LSR----LSU----lsack
TCP 6
udp17
OSPF field
Zone: Backbone area is 0, non-backbone zone not 0 must be connected directly to backbone area
Router type:
ABR: Zone border Router
ASBR: Autonomous system Border router There are both OSPF and RIP have translation routes
Backbone routers: As long as there is an interface in the 0 zone
Internal router: If two interfaces are in the same area as the internal router
Router-id: (1) The administrator is configured by command, (2) loopback Port IP Address
(3) the smallest IP address on the router if there are 3 interfaces with the smallest IP of the
router OSPF 10 (process number)
Network 192.168.1.0 0.0.0.255 area 0
strong> 88
STP: Spanning Tree protocol The basic configuration is not configured in the enterprise, but the function is to be opened to prevent
Election process: 0-65535 32768 default Small
(1) Select the root bridge, according to bid minimum priority +mac
(2) Each non-root bridge Select the root port, according to the root path cost is lowest, the direct connection Bridge ID is the smallest, direct connection port ID minimum
(3) Each physical network segment select the specified port, according to the same root bridge is
(4) The root port and the specified port are in the forwarding state, neither the root port nor the specified port is blocked
The IP header has TTL and the two-layer data frame does not have a broadcast loop
STP status: Blocking, listening, learning, forwarding
Maximum Lifetime Max Age 20s from blocking to listening time
Forwarding delay: 15s from listening to learning, learning to forward, each need 15s

Acl
Standard: Number 99 can only check the source IP address, applied to the nearest exit direction from the target
Extension: 100-199 Check the source and destination IP addresses and protocol and segment numbers applied to the nearest ingress direction from the source
Named:
Access-list 1 Deny 192.168.1.0 0.0.0.255
Access-list Permit any

ACL rules are matched on a line-by-row basis, and once the match is applied immediately, no more rules are checked. If there are no rule matches, the default is denied

The first volume of TCP/IP routing technology
NAT: Network Address Translation
Function: Convert one network address to another network address India three-tier NAT because of lack of address
Classification:
Dynamic: Many-to-many
Static: One-to-one external publishing server
PAT: A pair of many pairs of Taichi

Cisco Cisco Summary