Network+ 7 Flashcards
Open Shortest Path First (OSPF): A link-state routing protocol that uses a metric of cost, which is based on the link speed between two routers. OSPF is a popular IGP because of its scalability, fast convergence, and vendor-interoperability.
OSPF
Intermediate System-to-Intermediate System (IS-IS): This link-state routing protocol is similar in its operation to OSPF. It uses a configurable, yet dimensionless, metric associated with an interface and runs Dijkstra’s shortest path first algorithm. Although IS-IS as an IGP offers the scalability, fast convergence, and vendor-interoperability benefits of OSPF, it has not been as widely deployed as OSPF.
IS-IS
Enhanced Interior Gateway Routing Protocol (EIGRP): EIGRP is a Cisco proprietary protocol. It is popular in Cisco-only networks, but less popular in mixed-vendor environments. Like OSPF, EIGRP is an IGP with fast convergence and is very scalable. EIGRP is more challenging to classify as a distance-vector or a link-state routing protocol.
By default, EIGRP uses bandwidth and delay in its metric calculation; however, other parameters can be considered. These optional parameters include reliability, load, and maximum transmission unit (MTU) size. Using delay as part of the metric, EIGRP can take into consideration the latency caused from the slowest links in the path. EIGRP uses information from its neighbors to help it select an optimal route (like distance-vector routing protocols).
However, EIGRP also maintains a database of topological information (like a link-state routing protocol). The algorithm EIGRP uses for its route selection is not Dijkstra’s shortest path first algorithm. Instead, EIGRP uses diffusing update algorithm (DUAL).
EIGRP
BGP is considered to be the routing protocol that runs the Internet, which is an interconnection of multiple autonomous systems. path-vector routing protocol, meaning that it can use as its metric the number of autonomous system hops that must be transited to reach a destination network. A network can simultaneously support more than one routing protocol through the process of route redistribution.
BGP
DNAT: In the preceding example, the inside local addresses were automatically assigned an inside global address from a pool of available public addresses. This approach to NAT is referred to as Dynamic NAT (DNAT). This is often referred to as “many-to-many,” as many inside local users (a network) are mapped to a pool of inside global addresses.
SNAT : statically configure the mapping of an inside local address (the IP address of your internal email server) to an inside global address (the IP address to which email servers on the Internet will send email for your company). This approach to NAT is referred to as Static NAT (SNAT). This is often called a “many-to-one” mapping.
(PAT), which allows multiple inside local addresses to share a single inside global address (a single publicly routable IP address). For this reason PAT is referred to as “many-to-one.”
DNAT/SNAT/PAT
PIM-DM uses a source distribution tree, meaning that an optimal path is formed between the source router in a multicast network (that is, the router closest to the multicast sender) and each last-hop router (the router closest to each multicast receiver). However, before this optimal source distribution tree is formed, traffic from the multicast source is initially flooded throughout the entire network. Obviously, this initial flooding of multicast traffic causes traffic to be sent to routers not needing the multicast traffic, and it can unnecessarily consume bandwidth on the links between routers. After this initial flooding occurs, if a router interface receives the multicast traffic, and that traffic is not needed by the router (or if the traffic is needed by the router, but on a different interface), the router interface sends a prune message to its neighboring router, asking that it be pruned off of the source distribution tree, After the router interface sends these prune messages, the resulting source distribution tree (the path over which the multicast packets flow) is an optimal path between the source router and the last-hop route. A benefit of PIM-DM is that an optimal path is formed between the source router and each last-hop router.
PIM-DM
PIM-SM uses a shared distribution tree. A shared distribution tree does not initially form an optimal path between a source router and each last-hop router. Instead, a multicast source sends traffic directly to another router, called a rendezvous point (RP). When another router in the multicast network wants to join the multicast distribution tree (because it received an IGMP join message from a client), that last-hop router sends a join message to the RP to join the shared distribution tree, The tree is called a shared distribution tree because all last-hop routers (routers with downstream multicast receivers) send join messages to the same RP. After a last-hop router receives the first multicast packet from the multicast source, it can see the IP address of the multicast source. Then, based on its unicast routing table, a last-hop router can form an optimal distribution tree and then prune off the branch of the tree connecting it to the RP. This behavior is called shortest path tree (SPT) switchover.
PIM-SM
WAN : Dedicated leased line = A connection interconnecting two sites.
Circuit-switched connection = A connection that is brought up on an as-needed basis. In fact, a circuit-switched connection is analogous to a phone call, where you pick up your phone, dial a number, and a connection is established based on the number you dial.
Packet-switched connection = Like a dedicated leased line, because most packet-switched networks are always on. However, unlike a dedicated leased line, packet-switched connections allow multiple customers to share a service provider’s bandwidth. Customers can buy a service-level agreement (SLA), which specifies performance metrics. Frame Relay (packet-switched connection) network allows multiple customers to connect to a service provider’s network, and virtual circuits (VCs, shown as dashed lines) logically interconnect customer sites.
circuit-switched etc …
WAN Data Rates : OC-1 = 51.84Mbps, OC-3 = 155.52Mbps, OC-12 = 622.08Mbps, OC-48 = 2.4Gbps, OC-192 = 9.6Gbps
WAN Technologies and BandWidth : Frame Relay = 56 Kbps to 1.544 Mbps, T1 = 1.544 Mbps = T3 = 44.736 Mbps, E1 = 2.048 Mbps, E3 = 34.4 Mbps, ATM= 155 Mbps to 622 Mbps, SONET = 51.84 Mbps (OC-1) to 159.25 Gbps (OC-3072)
LTE (Mobile Devices) : 100 Mbps data rate and 16 Gbps data rate for stationary devices, Tethering allows a smartphone’s data connection to be used by another device, such as a laptop
WAN Data Rates Etc …
WiMAX: Worldwide Interoperability for Microwave Access (WiMAX) offers wireless broadband access to fixed locations (as an alternative to technologies such as DSL) and mobile devices. Depending on the WiMAX service provider, WiMAX coverage areas could encompass entire cities or small countries.
HSPA+: Like WiMAX, Evolved High-Speed Packet Access (HSPA+) is a technology offering wireless broadband service. The maximum data rate for HSPA+ is 84Mbps.
radio frequency spectrum includes frequencies of 3KHz through 300GHz.
WiMAX Etc …
