دکتر محمد وند جلیلی

لیست دستورات و کامند های تجهیزات سیسکو

لیست دستورات و کامند های تجهیزات سیسکو
این مطلب حاوی لیست بسیاری از کامند های متداول در تجهیزات سیسکو شامل روتر ها و سوئیچ های این شرکت میباشد و برای کسانیکه میخواهند در آزمونهای شرکت سیسکو مانند CCNA , CCNP (BSCI,BCMSN,ISCW,ONT) , CCSP ( SND, SNRS , SNPA , IPS , CSVPN ) , CCIE (SECURITY/ROUTING & SWITCHING/VOICE )
شرکت کنند بسیار ضروری میباشد . امید است مورد توجه بازدید کنندگان عزیز واقع شود .
برای دیدن cisco ios command list به ادامه مطلب مراجعه کنید .

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PPP Configuration
encapsulation ppp
ppp authentication
ppp chap hostname
ppp pap sent-username
sh int ser 0 - use to view encapsulation on the interface

Frame-Relay Configuration
encapsulation frame-relay ietf - use IETF when setting up a frame-relay network between a Cisco router and a non-Cisco router
frame-relay lmi-type ansi - LMI types are Cisco, ANSI, Q933A; Cisco is the default; LMI type is auto-sensed in IOS v11.2 and up
frame-relay map ip 3.3.3.3 100 broadcast - if inverse ARP won't work, map Other IP to Your DLCI # (local)
keepalive 10 - use to set keepalive
sh int ser 0 - use to show DLCI, LMI, and encapsulation info
sh frame-relay pvc - shows the configured DLCI's; shows PVC traffic stats
sh frame-relay map - shows route maps
sh frame-relay lmi - shows LMI info
Keyboard Shortcuts
CTRL-P - show previous command
CTRL-N - show next command
SHIFT-CTRL-6 - Break


Notes

Static and Dynamic Routing

Static Routing - manually assigned by the Admin user entering the routes (Routed Protocols - IP, IPX and AppleTalk)
Dynamic Routing - generated/determined by a Routing Protocol (Routing Protocols - RIP I, RIP II, IGRP, EIGRP, OSPF, NLSP, RTMP)
Dynamic
1) With Dynamic Routing, routers pass information between each other so that routing tables are regularly maintained.
2) The routers then determine the correct paths packets should take to reach their destinations.
3) Information is passed only between routers.
4) A routing domain is called an Autonomous System, as it is a portion of the Internetwork under common admin authority.
5) Consists of routers that share information over the same protocol. Can be split into routing areas.

Distance Vector and Link-State Routing
Routing Protocols
I) Interior (within an autonomous system - AS - group of routers under the same administrative authority)
a) Distance Vector - understands the direction and distance to any network connection on the internetwork. Knows how
many hops (the metric) to get there. All routers w/in the internetwork listen for messages from other routers, which are sent
every 30 to 90 seconds. They pass their entire routing tables. Uses hop count for measurement. 1) Used in smaller networks
that are have fewer than 100 routers. 2) Easy to configure and use.3) As routers increase in number, you need to consider
CPU utilization, convergence time, and bandwidth utilization. 4) Convergence is due to routing updates at set intervals. 5) When
a router recognizes a change it updates the routing table and sends the whole table to all of its neighbors.
1) RIP - 15 hop count max
2) IGRP - 255 hop count max, uses reliability factor (255 optimal), and bandwidth
3) RTMP
b) Link State - understands the entire network, and does not use secondhand information. Routers exchange LSP?s (hello
packets). Each router builds a topographical view of the network, then uses SPF (shortest path first) algorithm to determine the
best route. Changes in topology can be sent out immediately, so convergence can be quicker. Uses Bandwidth, congestion for measurement; Dijkstra's algorithm;
1) Maintains Topology Database. 2) Routers have formal neighbor relationship. 3) Exchanges LSA (Link State Advertisement) or
hello packets with directly connected interfaces. 4) These are exchanged at short intervals (typically 10 sec). 5) Only new info is
exchanged. 6) Scales well, however link?state protocols are more complex. 7) Requires more processing power, memory, and bandwidth.
1) OSPF - decisions based on cost of route (metric limit of 65,535)
2) EIGRP - hybrid protocol (both Distance-Vector and Link State), Cisco proprietary
3) NLSP
4) IS-IS
II) Exterior
1) EGP (Exterior Gateway Protocol)
2) BGP (Border Gateway Protocol)


Routing Protocols used for each Routed Protocol
IP - RIP, IGRP, OSPF, IS-IS, EIGRP
IPX - IPX RIP, NLSP, EIGRP
AppleTalk - RTMP, AURP, EIGRP

Problems with Routing Protocols
1) Routing Loops - occur when routing tables are not updated fast enough when one of the networks becomes unreachable. Due to theslow convergence (updates of routing table between all routers), some routers will end up with incorrect routing table and will broadcast that routing table to other routers. This incorrect routing tables will cause packets to travel repeatedly in circles.
2) Counting to infinity - occurs when packets end up in a routing loop; hop count increases with every pass through a router on the network Solutions to Problems with Routing Protocols1) Define the maximum number of hops - Whenthe number of hops reaches this predefined value, the distance is considered infinite, thus the network is considered unreachable. This does stop routing loops, but only limit the time that packet can travel inside the loop.
2) Split horizon - The packets can not be sent back to the same interface that they originally came from. During the updates, one router does not send updates to the router that it received the information from.
3) Route poisoning - The router sets the cost/distance of routes that are unreachable to infinity. Used with hold-down timers
4) Triggered updates - The router sends updates of the routing table as soon as it detects changes in the network. Does not wait for the prescribed time to expire.5) Hold-Downs - After the router detects unreachable network, the routers waits for a specified time before announcing that a network is unreachable. The router will also wait for a period of time before it updates its routing table afterit detects that another router came online (Router keeps an entry for the network possibly down state, allowing time for other routers to re-compute for this topology change). Hold-downs can only partially prevent counting to infinity problem. Prevents routes from changing too rapidly in order to determine if a link has really failed, or is back up
Encapsulation Types
Encapsulation 802.2 sap 802.3 novell-ether Ethernet II arpa (Internet Standard) Snap snap
Wan Service Providers
1) Customer premises equipment (CPE) - Devices physically located at subscriber?s location; examples: CSU/DSU, modem, wiring on the customer's location
2) Demarcation (or demarc) - The place where the CPE ends and the local loop portion of the service begins. (Usually in the "phone closet").
3) Local loop - Cabling from the demarc into the WAN service provider?s central office; wiring from customer's location to the nearest CO
4) Central Office switch (CO) - Switching facility that providesthe nearest point of presence for the provider?s WAN service; location of telephone company's equipment where the phone line connects to the high speed line (trunk); Regional Telco Office where the local loop terminates (the Telco location nearest you)
5) Toll network - The switches and facilities, (trunks), inside the WAN provider?s "cloud."

DTE - the router side and receive clocking
DCE - the CSU/DSU side and provide clocking
WAN Devices
Routers - Offer both internetwork and WAN interface controls
ATM Switches - High-speed cell switching between both LANs and WANs
X.25 and Frame-Relay Switches - Connect private data over public circuits using digital signals
Modems - Connect private data over public telephone circuits using analog signals
CSU/DSU (Channel Service Units/Data Service Units) - Customer Premises Equipment (CPE) which is used to terminate a digital circuit at the customer site
Communication Servers - Dial in/out servers that allow dialing in from remote locations and attach to the LAN
Multiplexors - Device that allows more than one signal to be sent out simultaneously over one physical circuit
ISDN
ISDN BRI (Basic Rate Interface) - 2 64K B channels, plus 1 16K D channel
ISDN PRI (Primary Rate Interface) - 23 64K B channels, plus 1 64K D channel (North America & Japan), 30 64K B channels, plus 1 64KD channel (Europe & Australia)

Classful and Classless Protocols
Classful - summarizes routing info by major network numbers; ex. RIP, IGRP
Classless - BGP, OSPF
Administrative Distances for IP Routes

Administrative Distances are configured using ip route command:

Example: ip route 154.4.55.0 255.255.255.0 195.23.55.1 85 (where 85 is the administrative distance)

IP Route
Administrative Distance
Directly connected interface
0
Static route using connected interface
0
Static route using IP address
1
EIGRP summary route
5
External BGP route
20
Internal EIGRP route
90
IGRP route
100
OSPF route
110
IS-IS route
115
RIP route
120
EGP route
140
External EIGRP route
170
Internal BGP route
200
Route of unknown origin
255

Switching Terminology
Store-and-Forward ? copies entire frame into buffer, checks for CRC errors before forwarding. Higher latency.
Cut-Through ? reads only the destination address into buffer, and forwards immediately; Low latency; "wire-speed"
Fragment free ? modified form of cut-through; switch will read into the first 64 bytes before forwarding the frame. Collisions will usually occur within the first 64 bytes. (default for 1900 series).
Access Lists
1-99 IP Standard Access List 100-199 IP Extended Access List 200-299 Protocol Type-code Access List 300-399 DECnet Access List 600-699 Appletalk Access List 700-799 48-bit MAC Address Access List 800-899 IPX Standard Access List 900-999 IPX Extended Access List 1000-1099 IPX SAP AccessList 1100-1199 Extended 48-bit MAC Address Access List 1200-1299 IPX Summary Address Access List
Access List Filters Wildcard Masks Additional Notes Standard IP Source IP address field in the packet's IP header To put simply, when the IP is broken down to binary, the 1's allow everything and the 0's must match exactly. Wildcard mask examples: 0.0.0.0=entire address must match. 0.255.255.255=only the first octet must match, the rest will allow everything. 255.255.255.255=allow everything Extended IP Source IP or Destination IP, or TCP or UDP Source or DestinationPorts, or Protocol Same as standard The key word ANY implies any IP value is allowed, the keyword HOST implies the IP exactly has to match Standard IPX Packets sent by clients and servers, and SAP updates sent by servers and routers Configured as a hexadecimal number instead of binary -1 means any and all network numbers ( works like ANY) Extended IPX Source Network or Node, or Destination Network or Node, or IPX Protocol, or IPX Socket, or SAP Match multiple networks with one statement, again in hexadecimal The most practical use of the protocol type is for NetBIOS SAP Sent and received SAP traffic N/A Updates its own SAP tables. Again uses -1 to mean "ANY"
Troubleshooting Tools:
Ping Results
! success , timeout U destination unreachable ? unknown packet type & TTL exceeded Traceroute Results
!H router rec'd, but didn't forward because of access-list P protocol unreachable N network unreachable U port unreachable , timeout
Accessing Router with Terminal Emulation
Using HyperTerminal on a Windows machine adjust the following settings:
VT100 Emulation
Connection Speed: 9600 Baud
Data Bits: 8
Parity: None
Stop Bits: 1
Flow Control: None
On a Linux machine you may use Seyon or Minicom (at least one should come with your distribution).

Router Startup Sequence
POST
Bootstrap program loaded from ROM
IOS is loaded from either flash (default), TFTP, or ROM
IOS image loaded into low-addressed memory; hardware and software is determined
Config file is load from NVRAM; if no configuration exists in NVRAM, the initial configuration dialog will begin

Miscellaneous Notes
Multiple Loop Problems ? complex topology can cause multiple loops to occur. Layer 2 has no mechanism to stop the loop. This is the main reason for Spanning ? Tree Protocol.

Spanning-Tree Protocol (STP) IEEE 802.1d. ? developed to prevent routing loops; uses STA (Spanning-Tree Algorithm) to calculate aloop-free network topology; allows redundant paths without suffering the effects of loops in the network

Virtual LAN?s (VLAN's) ? sets different ports on a switch to bepart of different sub-networks. Some benefits: simplify moves, adds, changes; reduce administrative costs; have better control of broadcasts;tighten security; and distribute load. Relocate the server into a secured location.

HDLC (High-Level Data Link Control) - Link layer protocol for Serial links. Cisco Default. Supports the following modes: Normal Response Mode ? as per Secondary under SDLC; Asynchronous Response Mode allows secondary to communicate without permission; Asynchronous Balanced mode combines the two stations. Has lower overhead than LAPB but less error checking.
Modular Switch/VIP Syntax
type slot/port (example: e 2/1)
type slot/port-adapter/port (example: e 2/0/1