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57 Cards in this Set
- Front
- Back
MPLS
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multiprotocol label switching
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MPLS is an _____ standard
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OPEN
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What RFC defines MPLS?
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RFC 3031
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MPLS was previously Cisco proprietary ______________
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tag switching
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the multiprotocol in MPLS allows
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transport of different payloads
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MPLS can move Layer 2 at
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Ethernet
Frame Relay ATM |
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MPLS can move Layer 3 at
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IPv4
IPv6 |
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Label switching -
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switches traffic between interfaces based on local significant label values
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MPLS label switching is similar to how..
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Frame Relay or ATM switch uses input/output DLCIs and VPI/VCIs
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Why use MPLS?
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Transparent tunneling over SP Network
BGP free core saves routing table space on provider routers traffic engineering |
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traffic engineering
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distribute load over underutilized links
give bandwidth guarantees and detect failures quickly |
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MPLS offers _______ service to customers.
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L2/L3 VPN
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how many bytes is the MPLS header
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4
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MPLS header is used to
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switch packets
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MPLS Label stack encoding (RFC 3032)
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20 bit Label (locally significant)
3 bit EXP (class of service) BoS bit (defines last label in the label stack) 8 bit TTL (time to live) |
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BoS
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bottom of stack bit
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MPLS labels are bound to _____
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FECs (forwarding equivalency class)
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Router uses the MPLS _____ instead of CEF FIB or IP routing table to switch traffic
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LFIB (label forwarding info base)
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MPLS switching logic
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If traffic comes in if1 with label X send it out if2 with label Y
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IPv4 prefix and label can define the ____
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FEC
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FEC definition
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a group of packets that possess the same label and are all forwarding through the infrastructure in a common way
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MPLS network consists of
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PE/LER devices
P /LSR devices |
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PE /LER device properties
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provider edge router/label edge router
connect to customer edge (CE) devices receive unlabeled packets (like IPv4) and add label performs ip routing and MPLS lookups |
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add label to unlabeled packet
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AKA label push or label imposition
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P/LSR device properties
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provider router/label switch routers
connects to PEs and/or other P routers switch traffic based only on MPLS label |
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MPLS PE and P router three major operations
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Label Push
Label Swap Label Pop |
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Label Push
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add a label to an incoming packet
AKA label imposition |
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Label Swap
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replace the label on an incoming packet
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Label pop
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remove the label from an outgoing packet
AKA label disposition |
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The ip prefix and the layer 2 circuit typically make up the _____
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FEC
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If a core MPLS router receives a labeled packet and there is no entry in the LFIB, the router does what?
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drop the packet
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Penultimate meaning
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next to last
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PHP
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Penultimate Hop Popping
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Label mapping information is advertised using a
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Label distribution protocol
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TDP
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Tag distribution protocol
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TDP uses what port for UDP broadcast to discover neighbors?
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711
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TDP uses what TCP port to setup a session after discovering neighbor
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711
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LDP
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label distribution protocol
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LDP uses UDP multicast to what group address
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224.0.0.2
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What UDP port is used with LDP for neighbor discovery?
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646
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What TCP port is used LDP for session setup between neighbors?
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646
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By default, the IP TTL is copied into the MPLS
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TTL field
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MPLS VPN two basic components
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Separation of customer routing information
Exchange of customer routing information |
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VRF
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Virtual Routing and Forwarding
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Each VRF has its own
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routing table
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Routing inside a VRF
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static routes
RIP EIGRP OSPF IS-IS MP-BGP Policy routing |
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How do PE routers exchange VRF info?
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MP-BGP (VPNv4)
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VPNv4 uses ___ byte route distinguisher
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8
unique per VPN or per VPN site |
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VPNv4 uses ___ byte IP address
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4
Unique per VPN |
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VPNv4 does include the MPLS label
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True
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route distinguisher used solely to make routes
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unique
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BGP extended community "route-target" used to control what enters/exits...
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VRF table
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export route target
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what routes will go from VRF into BGP
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import route target
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what routes will go from BGP into VRF
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allows control on a per prefix basis importing/exporting routes on VRF
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import/export map
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BGP Extended community byte size
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8
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VPNv4 speakers only accept VPNv4 routes with a route-target matching a local....
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VRF
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