CCNA review preparation content
• Network Basic Review • OSI Model Basics • TCP / IP Topics • VLSM Technology • Network Device Basics • Cisco Basic Commands • Switch Working • Generative Tree Principle • VLAN Technical Principles • Routing Foundation • Dynamic Routing Protocol Detailed (RIP, IGRP) • OSPF, EIGRP Brief Introduction • Access-List Principle and Implementation • NAT Technology Introduction • WAN Basis (PPP) • ISDN Related Concepts and Implementation • Frame-Relay Related Concepts and Implementation
Some knowledge points summary
Some selective ranges:
Interface sub-interface: 0 ~ 4294967295history size: 0 ~ 256BANDWIDTH: 1 ~ 100000 (kbps) Administrative Distant: 0 ~ 255AS: 1 ~ 65535IP OSPF Cost: 1 ~ 65535OSPF process ID: 1 ~ 65535ospf priority: 0 ~ 255ospf area: 0 ~ 4294967295 (However, the topic can be said to use 0 ~ 65535 nor wrong) standard ACL number: 1 ~ 99, 1300 ~ 1999 expanded ACL number: 100 ~ 199,200 ~ 2699frame-relay interface-dlci: 16 ~ 1007LMI reserved DICL Number: 1019 ~ 1022 port number: 0 ~ 65535Dialer-group: 1 ~ 10
------------------------------ UDP: TFTP SNMP DHCP BOOTP
NTP
Port
: 69 161/162 67/68 67/68 123
TCP: FTP HTTP SMTP TACACS Telnet NNTP HTTPS POP3port: 21/20 80 25 49 23 19 443 110
DNS Use Both TCP & UDP with Port 53 --------------------------------
Lapb for x.25lapd for isdn, using signaling standards for D Channel LAPM for MODEMS LAPF for Frame-Relay Frame Relay All frame formats are defined by LAPF, including DE, FECN, BECN, LMI, etc. More than the bonus of the HDLC protocol
--------------------------------- OSPF DR / BDR Election Conditions: Based on two conditions: 1, each router PRIORITY of the interface. 2, each Router's RouterID first looks at Priority. Router has a priority property, in the broadcast multiplexing network, priority is defamely 1. You can modify it with IP OSPF Priority in the interface. The smaller the value of Priority (except 0, priority is 0 means not participating in the DR / BDR election), the higher the priority. The Router where the interface with the highest priority priority is selected as DR, the second high is selected as BDR. When PRIORITY is equal, look at RouterID. When Router does not configure loopback port, The Highest Local Active IP Address Is ITS OSPF Router ID. When it is equipped with loopback, use a plurality of LoopBack ports with IPs with multiple LoopBack ports. (In actual work, it is generally recommended to configure a LoopBack port IP with a mask of 255.255.255.255 to ensure the stability of the system). The Routerid's highest Router is selected as DR, and the second high is selected as BDR. RouterID is only related to each port ip-address, and it has nothing to do with it, it is the lowest of the priority, but its IP-address is the highest, Router still uses its IP-address to Routerid, but this Router cannot be DR, BDR . Once the DR / BDR is selected, it will no longer change, even if the network is added to the new Router With Higher Ospf Priority Values.Ospf electoral process to exchange information with a Hello package. Election Conditions for Root Bridge in Switch STP: Based on BridgeID. Switch's bridgeid has a total of 8 bytes, the first two bytes are the priority of Switch, and the last six bytes are the MAC address of the port. First of all, PRIORIT
Y, the smallest is selected as root bridge. The priority default is 32768. When priority is the same, the MAC address is compared, and the minimum is selected as root bridge. Root Bridge's election process exchange information with BPDU packages. ----------------------------------
About several packages 1, in VLAN TRUNKING, ISL (Cisco dedicated) and DOT1Q (universal). The Switch 1900 can only be used on the use of DOT1Q, 2900 on both 2950. The related pictures are as follows: Command: Router: (config-subif) #ENCAQSulation ISL / DOT1Q {VLAN #} 2900 Switch: (config-if) #Switchport Trunk Encapsulation ISL / DOT1Q
2
3, Frame-Relay Package: Cisco (Cisco Special, Default) IETF (General) Command: (Config-IF) #ENCAPSulation Frame-Relay [IETF] Cisco is the default parameter, no writing configuration
4, Frame-Relay LMI package: Cisco (Cisco dedicated, default) ANSI (ANSI standard) Q
933A
(ITU Standard) In Cisco IOS 11.2 or later, the LMI type is automatically adapted, and it is generally not necessary. All of the above packages are required to communicate with the peer of communication. ----------------------------------
SPANNING-TREE Protocolvtp: VLAN Trunking Protocolrtp: Reliable Transport Protocolspf: Shortset Path First
