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What is Autonomous System (AS)? |
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One or more networks that are governed by a single protocal within that AS. AS's do not use IP addresses, but use a special globally unique Autonomous System Number(ASN) assigned by the IANA. |
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What is Border gateway prootocal(BGv-4)? |
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the current verssion of the external routing protocol used on the internet. (BGP -4) is used for communications between Autonomous Systems. |
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What isCisco IOS |
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A proprietary operating system that runs on most Cisco products |
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What is Convergence |
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A state in whiach all routers within an area are up-to-date, and their routing tables all match |
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What is Destination NAT |
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A type of Network Address Translation(NAT) in which the destination IP addresses is translated by the NAT -capable router. |
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What is Destination port |
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A fixed predetermined number assigned to a packet by the sending computer; it defines the function r session type. Destination port numbers are commonly in the range of 0 to 1023. |
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Whats is distance vector? |
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A routing protocal that calculates the total cost to get to a particular network ID and compares that to the cost to the total cost of all the other routes to get that same network ID. The router then chooses the route with the lowest cost. |
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What is a Dynamic Nat? |
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A type of network address translation (NAT) in which many computers can share a pool of routable (non-public) IP address that number fewer then the computer. |
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What is Dynamic Routing? |
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A process by which routers in a network in an internetwork automatically exchange information with all other routers, enabling them to build there own list of routers to various networks. |
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What is a Edge Router |
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A router used to communicate between Autonomous Systems to corresponding edge routers in other Autonomous Systems. |
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What is Enhanced Interior Gateway Routing Protocal(EIGRP) |
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Its a Cisco-proprietary protocal developed to work in enterprise-wide routing environments. |
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What is a Ephemeral Port? |
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An arbitary number assigned to a packet by the sending computer: the recieving computer uses this with the destination address so that the sending computer knows which application to use the returning packet. Common ephemeral port numbers are in the range of 1024-500. |
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What is a gateway router |
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A router that acts as the default gateway for a number of client computers. |
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Whats a hop? |
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Its one trip through a router by a packet. |
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What is Intermediate System to Intermediate System(IS-IS) |
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A link-state dynamic routing protocal(one that announces and forwards individual route changes as they appear), using the concept of areas. Its a major advantage over OSPF(another link-state routing protocal)) is that it is has supported IPv6 from the start. Its not nearly as popular as OSPF. |
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What is a Link-state? |
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A dynamic routing protocal that is more efficent then RIP, announcing and forwarding individual route changes as they appear,rather then sending the entire routing table. The two link-state dynamic-routing protocal are OSPD and IS-IS. |
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What is a Managed device? |
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A router or advanced switch that can be configured through a software interface-often via a terminal emulation program. |
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What is a Metric? |
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A relative value that defines the "cost" of using a router. |
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What is a Nat translation table? |
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A means of traslating a systems IP address into another IP address before sending it out to a larger network, in order to hide the IP address on a private network. |
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What is the Next Hop? |
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Where a packet should go when its destination address has a network ID not directly connected to the router |
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Whats Open Shortest Path First(OSPF)? |
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Uses a link-state algorithm and shares more detailed information called link-state advertisements. |
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What is (OSPF) Area ID? |
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Identifiers assigned to routers in order to limit traffic to routers within a specified area/Area IDs resemble IP addresses.For isntance, a common practice is to give each router belonging to one group the Area ID 0.0.0.0, commonly called Area 0. |
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What is (OSPF) Designated router(DR)? |
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A router that has the function of relaying information to all the other routers in the area (In a networking using OSPF.) |
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What is (OSPF)Backup Designated router(BDR)? |
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A router within an autonomous system(AS) that is assigned the role of backup router to the AS's designated router.The BDR takes over whenever the DR is not available. |
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What is Overloaded NAT |
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The most popular type of NAT, using a single IP address, shared by a number of computers that, in turn, usally share a private network ID |
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What is port |
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In TCP/IP, a 16-bit number,between 0 and 65,535, assigned to a particular TCP/IP session. All TCP/IP packets ( except for some really low-level maintenance packets) contain port numbers that two communicating computers use to determine the kind of session to use, and how to get the packet or response back to the sending computer. |
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What is Port address Translation (PAT)? |
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A term used by manufactures to refers to either overloaded nat or port forwarding. |
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What is Port Forwarding? |
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A NAT function that hides a prot number from outside networks,enambling public servers to work behind a NAT router. It gives a server on a private network the protection of NAT, while allowing access to that server from outside the private network. |
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What is RIPv1? |
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A distance-vector routing protocal, dating from the 80s, that has maximum hop count of 15. RIP routers sent out updates every 30 seconds, causing huge network overloads. It was also limited to only working with classful addresses, not recongizing CIDR subnets. Plus, it had no authorization mechanism, leaving RIPv1 routers open to hackers sending false routing table info. |
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What is RIPv2? |
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The current version of the RIP distance vector routing protocal that was adopted in 94. It fixes many of the problems with RIPv1. It had CIDR addressing, updates at random intervals, and has a built in authentication protocal. It still has the 15 hop limit and time-to-convergence problems on large WANs,so its considered obsolete for all but small,private WANs. |
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What is a Router? |
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A device connecting separate networks, which forwards a packet from one network to another based only on the networks address of the protocal being used. |
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what is Routing information Protocal? |
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A distance-vector routing protocal that,to date, has had two versions, RIPv1, RIPv2. Both versions have a max hop count of 15. |
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What is a routing Table? |
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A table used by a router to determin where to send each packet, based on its destination network ID address. |
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What is a source NAT? |
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A type of network address Translation(nat) in which the source IP addresses are translated by the NAT-capable router. |
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What is a static NAT(SNAT)? |
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A type of network address translation in which the router maps a single routable (non private) IP address to a single machine,enabling you to access that machine from a outside the network. The NAT keeps track of the IP address or addresses , and applies them permanently on a one-one basis with computers on the network. |
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what is static route? |
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Network routes that are entered into a routers routing table manually. |
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What is a TRACEROUTE? |
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Its a utililty software that records the route between any two hosts on an internetwork. Like ping, TRACEROUTE sends a single packet to another host, but unlike ping, as the packet progresses, it returns infomation about every router between hosts. |
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What is a Yost cable? |
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A special serial cable used to connect to a cisco-brand router in order to perform the inial configuration on the router. |
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