Chapter 1 - Define Key Terms Flashcards
(42 cards)
Define:
Multiprotocol BGP (MBGP)
Also known as BGP+. Adds following capabilities to BGP:
- enable multicast routing policy throughout the Internet
- connect multicast topologies within and between BGP autonomous systems
MP-BGP carries two sets of routes, one set for unicast routing and one set for multicast routing. PIM is used to build multicast data distribution trees.
Define
Bidirectional Forwarding Detection (BFD)
A detection protocol designed to provide fast forwarding path failure detection times for all media types, encapsulations, topologies, and routing protocols. Also provides consistent failure detection method for network administrators.
Define
First Hop Redundancy Protocol (FHRP)
Network protocol that offers default gateway redundancy by allowing two or more routers to provide backup for the IP address of the default gateway.
Define
Virtual Router Redundancy (VRR)
Cisco proprietary redundancy protocol for establishing a fault-tolerant default gateway, described in detail in RFC 2281.
Define
Gateway Load Balancing Protocol (GLBP)
Cisco proprietary protocol feature that provides automatic router backup for IP hosts configured with a single default gateway on an IEEE 802.3 LAN.
Define
link-state advertisements (LSAs)
The link-state advertisement created by the OSPF designated router (DR) or pseudo node that represents a group of routers on the same interface. The network LSA advertises summary information to represent the group of routers on the network.
Define
Shortest Path First (SPF)
A routing algorithm that iterates on length of path to determine a shortest-path spanning tree. Commonly used in link-state routing algorithms. Sometimes called Dijkstra’s algorithm.
Define
Virtual Internet Routing Lab (VIRL)
Cisco virtual machines running the same network operating systems as used in the Cisco physical routers and switches.
Define
Virtual Device Context (VDC)
Partitions a single physical device into multiple logical devices that provide the following:
- fault isolation
- management isolation
- address allocation isolation
- service differentiation domains
- adaptive resource management
A VDC instance can be managed within a physical device independently. Each VDC appears as a unique device to the connected users. A VDC runs a separate logical entity within the physical device, maintains its own unique set of running software processes, has its own configuration, and can be managed by a separate administrator.
Define
equal-cost multipath (ECMP)
Multiple routing paths of equal cost that may be used for packet forwarding.
Define
autonomous system (AS)
A collection of networks under a common administration sharing a common routing strategy. Autonomous systems are subdivided by areas. An autonomous system must be assigned a unique 16-bit number by the IANA.
Define
Interior Gateway Protocol (IGP)
Internet protocol used to exchange routing information within an autonomous system.
Define
Virtual Routing and Forwarding (VRF)
A VPN routing and forwarding instance. A VRF consists of an IP routing table, a derived forwarding table, a set of interfaces that use the forwarding table, and a set of rules and routing protocols that determine what goes into the forwarding table.
Define
time-to-live (TTL)
A field in an IP header that indicates how long a a packet is considered valid.
Define
Switched Virtual Interface (SVI)
A virtual interface (and port) that transmits only an untagged-VLAN packet for a managed switch.
Define
Link Aggregation Control Protocol (LACP)
The IEEE standard for Ethernet. LACP (802.3ad) for the gigabit interfaces feature bundles individual Gigabit Ethernet links into a single logical link that provides the aggregate bandwidth of up to four physical links.
Define
generic routing encapsulation (GRE)
A tunneling protocol developed by Cisco that can encapsulate a wide variety of network layer protocols inside a virtual point-to-point link to Cisco routers at remote points over an IPO internetwork. By connecting multiprotocol subnetworks in a single-protocol backbone environment, IP tunneling using GRE allows network expansions across a single-protocol backbone environment.
Define
Protocol-Independent Multicast (PIM)
A multicast routing architecture that enables the addition of IP multicast routing on existing IP networks. PIM is unicast routing protocol independent and can be operated in two modes: dense and sparse.
Define
shortest path tree (SPT)
A source tree represents the shortest path that the multicast traffic takes through the network from the sources that transmit to a particular multicast group to receivers that requested traffic from the same group. Because the characteristics of a source tree, this tree is often referred to as a shortest path tree (SPT).
Define
Reverse Path Forwarding (RPF)
Because multicast traffic is destined for an arbitrary group of hosts, the router uses Reverse Path Forwarding to route data to active receivers for the group. When receivers join a group, a path is formed either toward the source (SSM mode) or the RP (ASM or Bidir mode). The path from a source to a receiver flows in the revers direction from the path that was created when the receiver joined the group.
For each incoming multicast packet, the router performs an RPF check. If the packet arrives on the interface leading to the source, the packet is forwarded out each interface in the outgoing interface (OIF) list for the group. Otherwise, the router drops the packet.
Define
Multicast Listener Discovery (MLD)
In IPv6, multicast group management is accomplished with a set of ICMPv6 messages that comprise the Multicast Listener Discovery (MLD) protocol. MLDv1 is similar to IGMPv2 and MLDv2 is similar to IGMPv3. Like IGMP, MLDv2 is backward compatible with MLDv1.
Define
source-specific multicast (SSM)
Source-specific multicast (SSM) is a PIM mode that builds a source tree that originates at the designated router on the LAN segment that receives a request to join a multicast source. Source trees are built by sending PIM join messages in the direction of the source. The SSM mode does not require you to configure RPs.
Define
any-source multicast (ASM)
Any-source multicast (ASM) is a PIM tree building mode that uses shared trees to discover new sources and receivers as well as source trees to form shortest paths from receivers to sources. The shared tree uses a network node as the root, called the rendezvous point. The source tree is rooted at first hop routers, directly attached to each source that is an active sender. The ASM mode requires an RP for a group range. An RP can be configured statically or learned dynamically by the Auto-RP or BSR group-to-RP discovery protocols. If an RP is learned and is not known to be a Bidir RP, the group operates in ASM mode.
Define
Internet Group Management Protocol (IGMP)
Used by IP routers and their immediately connected hosts to communicate multicast group membership states.
