4A0-C01 Questions and Answers

Not So Stubby Areas

Level 1 Areas

Stub Areas

Partially Stubby Areas

Provides a mechanism to determine the hops an SDP traverses.

Provides in-band uni-directional connectivity tests.

Provides in-band round-trip connectivity tests.

Tests ability of reaching the far-end IP address of an SDP ID within the SDP encapsulation.

Provides information regarding the exact MTU supported between service ingress and service termination.

TRUE

FALSE

Configuring an Epipe service with a customer ID

Defining a SAP or SAPs.

Binding to an SDP if it is a distributed service.

Enabling the service using the no shutdown command.

Creating and assigning an IP filter to the SAP.

Configuring QoS parameters

It will show the hops taken between service endpoints.

It will test the delay across the service.

It will test the SDPs of a service in both directions.

It will test the round-trip connectivity of the service.

The default service MTU on a VPLS service is 1514 bytes.

The default IP MTU of an IES is set based on the network port MTU.

During VC label signaling, the VC MTU is verified and must match.

All of the above.

Change the service MTU of the VPLS to match the IES.

Set the ip-mtu of the IES service to match the service MTU of the VPLS service.

Change the MTU of the SDP attached to the VPLS to match the service MTU of the VPLS.

Set the DNF flag on the IES service.

Multiple MP-BGP sessions are required to carry VPN-IPv4 and VPN-IPv6 routes.

PE routers must support both IPv4 and IPv6 addresses; customer routers can use either one

In 6VPE, MP-BGP is used to advertise IPv6 prefixes and the associated VPRN label.

In 6VPE, the provider core routers are IPv6-unaware.

All of the above statements are true.

All of the above statements are false.

Set the service MTU of the VPLS to match the IES MTU.

Set the ip-mtu of the IES to match the service MTU of the VPLS.

Set the SDP MTU of the IES to match the SDP MTU of the VPLS.

Set the MTU of the IES's network port to match the service MTU of the VPLS.

No protocol extensions required

Only supported by OSPF and IS-IS

Transparent to routing neighbors

Uses Graceful Restart to inter-operate with other vendors

An L1 adjacency will be formed.

An L1/L2 adjacency will formed

L2 adjacency will be formed

No adjacency will be formed

They are explicitly acknowledged by sending a CSNP to the sender identifying the LSP.

They are implicitly acknowledged as a part of the link-state database synchronization and maintenance procedures.

They are explicitly acknowledged by sending a PSNP to the sender identifying the LSP.

They are implicitly acknowledged by the DIS multicast of CSNPs.

VPRN is an IP service that connects multiple sites in a single routed domain over the provider-managed IP/MPLS network.

Each VPRN consists of a set of customer sites that must connect to the same PE router

In a VPRN service, each customer router becomes a routing peer to other customer routers

VPRN provides customer routers with transparent IP connectivity without knowledge of the MPLS core

L1 routers in the same area

L1 routers in other areas

L2 routers in the same area

L2 routers in other areas

L1/L2 router in the same area

L1/L2 routers in other areas

IP routing protocols do not always select the best route to a destination.

IP routing protocols always select multiple routes to a destination.

IP routing protocols do not make use of all available network attributes to select a path

Improper network design results in limited network path redundancy.

RIB

FIB

LIB

LFIB

The neighbor's link-state database has newer information than what it received in the update.

The neighbor sends the update as an acknowledgement.

The neighbor's update indicates that it has run out of space in its LSDB.

The neighbor's update indicates that the sequence number received is the same as the one already in its link-state database.

The PLR sends it downstream with the RRO.

The PLR sends it downstream with the ERO.

It associates all detours with the source PLR.

The MP sends it upstream with the RESV message.

10.10.10.2

10.10.10.3

10.10.10.4

10.10.10.6

There is no ASBR configured in the network.

Add the "originate-default-route" option in the NSSA area configuration on router R3.

Add the "summaries" option to the NSSA area configuration on router R1.

Configure a static route on router R1 to 192.168.3.1.

Configure a default route on router R2.

LSPs must always terminate on a system ID.

MPLS and RSVP must be enabled on all routers.

Interfaces must be individually created in RSVP.

Path definitions must include at least one hop entry.

100Mbps

200Mbps

300Mpbs

600Mbps

700Mbps

Route redistribution is only needed if Internet access is a requirement.

Route filtering is the process of attaching data path filters to router interfaces.

Route filtering involves deciding whether to permit or deny certain routing updates from being accepted into, or distributed out of, the route-selection process.

Redistribution is needed for exchanging routes from one routing protocol to another.

OSPF routers that are redistributing routes must be configured as ABRs.

Administrative Groups

Shared Risk Link Groups

Strict hop LSP paths

Fast reroute

To advertise VPN-IPv4 and VPN-IFV6 routes, two MP-BGP sessions are required.

PE routers must support both IPv4 and IPv6 addresses; customer routers can use either one.

MP-BGP is used to advertise IPv6 prefixes and the associated VPRN labels.

The provider core routers are IPv6-unaware.

1512

1522

1536

1542

By default, the VC ID on the mesh SDPs of a VPLS are set to the service ID.

A VPLS appears to the customer as a direct Ethernet connection.

Mesh SDPs are used for VPLSes to avoid loops.

By default, T-LDP is used for signaling service labels.

The VC-IDs used between the E-pipe and VPLS must match.

The E-pipe must maintain a MAC FDB in order to connect to the VPLS.

The service ID of the E-pipe can be different from that of the VPLS.

The service MTU of the VPLS and E-pipe must match.

Tunnel Label

VC Label

Operational Control Word

VPI

VCI

L-LDP

T-LDP

RSVP-TE

MP-BGP

The service takes a route determined by the IGP.

The tunnel does not use a service label.

The service label is swapped at each hop in the transport network.

The tunnel is bidirectional and only requires configuration at one end of the service.

RSVP

IPCP

TLDP

PPP

Either RSVP or LDP

M-BGP

By default, a VPLS signals an MTU based on the network port.

By default, an IES sets its ip-mtu to the VC MTU of the VPLS.

By default, an IES uses an MTU value based on its SAP.

By default, an IES uses an MTU based on the network port.

TRUE

FALSE

Mesh SDPs assist MAC learning by flooding traffic to other mesh SDPs.

A PE keeps a single FDB for all VPLSes it has.

Frames received on a SAP that are broadcast, multicast or unknown are flooded.

The FDB only stores the MAC addresses of remote sites.

The original VLAN tag is removed.

The original VLAN tag is kept.

The VLAN tag is replaced by a provider tag.

The VLAN tag is kept and a provider tag is added.

The LSP can use facility and one-to-one FRR simultaneously.

The LSP is limited to node protection.

A single protection tunnel is used for all LSPs with the same path.

A detour protection tunnel is created for the LSP.

A logical entity that provides a uniform, end-to-end configuration, management and billing model for provisioning either Internet or VPN connectivity.

Provides connectivity between customer access points.

A service that can either be local or distributed.

All of the above

Option A

Option B

Option C

Option D

Next Header

Traffic Class

Flow Label

Payload Length

Options

The PLR issues a RSVP path message to the destination router to request the address of the MP.

The PLR learns the address of the MP from the ERO.

The PLR learns the address of the MP from the RRO

The PLR learns the address of the MP from the targeted RSVP hello message.

The PLR does not need to know the address of the MP.

1514

1526

1548

1556

1536

The matching outer tag is removed, and the frame is forwarded.

The inner tag is removed, and the frame is forwarded.

The inner tag is changed to match the SAP, and the frame is forwarded.

The frame is dropped.

0x4

0x5

0x10

0xa

The inner label will be exchanged with the MPLS outer label.

The inner label will be exchanged for a new label.

The outer label will be exchanged for a new label.

All labels will be exchanged for one new label.

All labels will be exchanged for an equal number of new labels.

16

20

24

25

32

RSVP LSPs must exist between each PE-ABR pair, or ABR-ABR pair in each area.

When LDP-over-RSVP is active, the LDP prefixes are resolved to a physical egress interface.

Targeted sessions must exist between all routers along the tunnel path.

Link LDP sessions must exist between each ABR-ABR pair in each area.

The SDP must be a mesh

The SDP must be a spoke.

Once the SDP is configured on both PE routers, both the services will be operationally up without further configuration changes.

The Layer 2 MTUs must match between the IES and the VPLS

The Layer 2 MTU must be 14 bytes smaller on the VPLS than it is on the IES.

A CE router.

A P router.

A PE router.

Both P and PE routers.

ADSPEC sets an SDP's MTU to the smallest MTU value found along the LSP path.

RSVP must be enabled on all MPLS routers of a path to use ADSPEC.

ADSPEC can automatically adjust the service MTU.

ADSPEC can be enabled on individual LSPs.

When a PE router receives an IPv4 prefix from its local CE, it creates a VPN-IFV4 prefix.

VPN-IPv4 allows BGP to distinguish between duplicate prefixes originating from different customers.

In a VPRN, data traffic is carried in packets that have VPN-IPv4 addresses.

VPN-IFV4 addresses are only present within the service provider network.

The service label is swapped for a transport label during transport.

The transport label is used to forward packets between PEs.

The service label is used to identify which VPRN a packet belongs to.

Labels are initially added at the ingress PE.

An IES has a configurable VC MTU.

An IES interface has an IP address assigned to it.

IES supports QoS.

An IES requires a spoke SDP.

MTU mismatch

Incorrect subnet mask

System interface not included in OSPF

Area ID not the same

Different metric set on each end of the link

Router ID not defined

They are type 7 within the area and are not modified at the ABR

They are type 5 within the area and converted to type 3 at the ABR

They are type 5 within the area and are not modified at the ABR

They are type 7 within the area and converted to type 5 at the ABR

Both routers will generate OSPF Hello packets.

The system interface is missing in one configuration so OSPF will not operate correctly.

The interface type settings differ, but OSPF will still operate correctly.

Metric values differ, but this does not prevent OSPF operation.

Send a PathTear message towards router R6.

Send a PathTear message towards router R1.

Send a ResvTear message toward router R6.

Send a ResvTear message toward router R1.

An IGP route takes priority over a transport tunnel.

Both LDP and RSVP-TE based tunnels can be used.

MPLS tunnels can be used to resolve the prefixes learned via IGP.

Multiple MPLS tunnels can be installed in the FIB.

By default, a 7750 SR does not advertise all routes in the VRF to a CE router.

The default 7750 SR behavior describes all routes in a VRF that are advertised to other PE routers.

By default, a 7750 SR does not advertise all routes in the VRF to other PE routers.

By default, a 7750 SR advertises all routes in the VRF to a CE router.

1

4095

None. This encapsulation is not supported.

The number is limited only by the capacity of the router

An SDP can be used by more than one service and customer.

A SAP can only be created on an access port.

A customer can have multiple services associated to it.

A customer is only created on one site of a distributed service.

Tunnel Label

VC Label

Operational Control Word

VPI

VCI

sap 1/1/1

sap 1/1/1:*

sap 1/1/1:*.0

sap 1/1/1:0*

sap 1/1/1:200.*

sap 1/1/1:300:200

A packet arriving with label 131066 will be forwarded out interface 1 /1 /4 with label 131070.

The router is an egress router for FEC 10.10.10.221/32.

There are multiple LSPs to reach FEC 10.10.10.244/32.

The router's system address is 10.10.10.242/32.

Conservative label retention

Liberal label retention

Downstream on demand

Downstream unsolicited

config>router#

config>qos#

config>port#

config>service#

Drop the frame.

Flood the frame to all PEs participating in the service.

Send a destination unreachable message back to the originating host.

Store the frame until the destination is known

The system ID

The loopback address

The sequence number of the hello packet

The device that first initiated communication becomes the DIS

Configure router ipv6 static-route 2001:DB8:1:200::/56 next-hop FE80::225:BAFF:FE30:94E3

Configure router ipv6 static-route 2001:DB8:1:200::/56 next-hop FE80::225:BAFF:FE30:94E3-toR2

Configure router static-route 2001:DB8:1:200::/56 next-hop FE80::225:BAFF:FE30:94E3

Configure router static-route 2001:DB8:1:200::/56 next-hop FE80::225:BAFF:FE30:94E3-toR2

The route was learned through a dynamic routing protocol.

config> static-route 0.0.0.0/0 next-hop 10.1.2.2

config>router> static-route 0.0.0.0 255.255.255.255 next-hop 10.1.2.1

config>router> static-route 0.0.0.0/0 next-hop 10.1.2.2

config>router> static-route 0 0.0 0/0 next-hop 10.1.2.1

To establish additional LSPs across the network

To allow ECMP to occur across an MPLS network

To enable the implementation of services

To utilize paths other than the lowest cost path

Tunnel ID

Name

LSP ID

To

The router sends a copy of the LSP from its database to its neighbor.

The router sends a PSNP to its neighbor describing the LSP in its database.

The router updates its database with the LSP and floods a copy to its other neighbors.

The router sends a PSNP to its neighbor to request the LSP.

A default route on router R2 to router R1.

A default route on the PC to router R2.

A static route on the PC to router R2 and a static route on router R2 to the PC.

A default route on router R1 to router R2.

One.

One for each of the routers in area 0

One for each of the external routes exported by router R1.

Type 4 LSAs are not generated in this network topology.

Show route-table

Show router routing-table

Show router route-table

Show static

49.0012.1234

49.0012

12.1234

1234

49.1234

The prefix list reject should be "192.168.3.0/16 exact".

Router R1 should be configured as an OSPF "asbr".

The policy "reject" should be set for import rather than export.

The policy was likely not "committed" after creation.

This is not possible because OSPF cannot use import policies.

The DIS creates a logical node to represent a group of routers on the same non-broadcast network; this node is the pseudonode

The DIS creates a logical node to represent the topological database of the backbone network in an IS-IS network; this node is the pseudonode

The DIS creates a logical node to represent a broadcast sub-network; this node is the pseudonode

The DIS creates a logical node to represent the complete topology of an IS-IS area; this node is the pseudode

traceroute 2.3.4.1

traceroute 2.3.4.0/24 next-hop 1.2.3.4

traceroute next-hop 1.2.3.4

traceroute does not work on the Alcatel-Lucent 7750 SR

The Maximum Allocation Model (MAM) provides the most efficient bandwidth utilization model

In the Maximum Allocation Model (MAM), each CT receives dedicated bandwidth constraints.

In the Russian Doll Model (RDM), a CT2 LSP automatically preempts a CT1 LSP.

Using the Russian Doll Mode! (RDM), a CT1 LSP may use unreserved CTO bandwidth.

A POP label stack operation may be performed.

The outgoing interface and next-hop address will be determined from the FIB.

The packet can be forwarded as a labeled or unlabeled packet.

A PUSH label stack operation may be performed.

Stub must be configured on Area 1 of router R1, and removed from Area 1 on router R3.

Stub must be configured on Area 1 of router R1 and Area 1 of router R3.

Stub must be configured on Area 0 of router R1 and Area 1 of router R3.

Area 1 of router R3 should be Area 0, in order to connect via stub to router R1.

It uses a UDP connection with an arbitrary port number.

It uses a UDP connection with well known port number 646.

It uses a TCP connection with an arbitrary port number.

It uses a TCP connection with well known port number 646.

Router address

Traffic engineering metric

Maximum bandwidth

Link

Admin Group

Admin groups can be configured using the command "configure>router>mpls>admin-group".

CSPF uses the information defined by admin groups when paths are computed for constraint-based LSPs.

By default, interfaces for which MPLS has been enabled are in the default admin group.

A LSP can make use of admin groups for constraint-based path calculations by including or excluding the admin group

Link

Intra-Area Prefix

Inter-Area Prefix

Inter-Area Router

Ordered control mode; downstream on demand.

Ordered control mode; downstream unsolicited.

Independent control mode; downstream on demand.

Independent control mode; downstream unsolicited.

Router R1

Router R4

Router R2

Router R3

CSNPs are used to maintain consistency in the Link-State database.

CSNPs are advertised before an adjacency is formed with another router.

There are two types of CSNPs: Level 1 and Level 2.

The CSNP lists the LSPs in the router's database

Router R2 sends an update to 224.0.0.5 on its broadcast and point-to-point interfaces. The DR does not send any updates.

Router R2 sends an update to 244.0.0.5 on its point-to-point interfaces. The DR sends an update to 224.0.0.6 on the broadcast network.

Router R2 sends an update to 224.0.0.5 out its point-to-point interfaces and an update to 224.0.0.6 out its broadcast interface. The DR sends updates to 224.0.0.5 on the broadcast network.

Router R2 sends an update to 224.0.0.6 out its point-to-point interfaces and an update to 224.0.0.5 out its broadcast interface. The DR sends an update to 224.0.0.6 on the broadcast networks.

To reduce the size of each routing update.

To allow interoperability between routing protocols.

To allow different subnet masks for different subnets.

To reduce the size of the routing table.

An L1/L2 router can have adjacencies with routers in different areas.

An L1/L2 router calculates separate SPF trees for the Level 1 and Level 2 topology.

An L1/L2 router advertises its L2 routes to other L1 routers in the same area.

An L1/L2 router sets the ATT bit in L1 LSPs to indicate that it has routes to other areas.

A new LDP session is established on R1-R3-R6 as soon as the FIB is updated.

The LDP session remains unchanged until the existing path R1-R2-R4-R6 goes down.

A new LDP session is established on R1-R3-R6 as soon as router R1 receives a new label for router R6.

The LDP session remains unchanged until router R3 stops advertising the maximum metric for the link to router R6.

Route distinguishes are 12 bytes in length

Route distinguishes are appended to IPv4 prefixes to form 16 byte VPN-IFV1 prefixes.

Route distinguishes are used to determine which routes a VPRN should import.

CE routes must be configured with the proper route distinguishes for the VPRN they are associated to

All of the above statements are true.

All of the above statements are false.

A virtual routing/forwarding table is created per IES service.

Only one IES service can be created for a single customer ID.

More than one IP interface can be created within a single IES service.

All IP interfaces created within the same IES service belong to the same customer

The path must include at least one hop.

The path may be used for multiple LSPs.

The path may be used multiple times in a single LSP.

The path must define a tunnel destination IP address.

Service ID

Customer ID

SAPID

VC-ID

SDPID

A data packet will receive a service label at the CE and a transport label at the ingress PE.

A data packet intended for a remote CE will have its service label swapped at each P router along the path towards the egress PE.

At the egress PE, the transport label will be popped and the data packet forwarded with the service label.

The service label is popped by the remote CE. The unlabeled packet is forwarded based on the longest match lookup algorithm in the VRF.

All of the above statements are false.

All of the above statements are true.

The penultimate router will forward packets to the eLER, based on the IP header.

The eLER will receive packets with a top label value of 0.

The eLER will receive packets with a top label value of 3.

The penultimate router will pop the top label from the packets.

When the reserved bandwidth goes above 80M.

When the reserved bandwidth goes above 40M.

When an additional 80M bandwidth is reserved.

When an additional 40M bandwidth is reserved.

Layer 3 direct Internet access service.

Layer 2 point-to-point service.

Layer 2 multipoint-to-multipoint service.

Layer 3 IP multipoint-to-multipoint VPN service.

LSP-3 takes R1-R3-R5-R6 and LSP-4 takes R1-R2-R4-R6.

LSP-3 takes R1-R2-R4-R6 and LSP-4 takes R1-R3-R5-R6.

LSP-3 takes R1-R3-R5-R6 and LSP-4 has no available path.

LSP-3 takes R1-R2-R4-R6 and LSP-4 has no available path.

The customer maintains complete control over routing.

The adding of new sites is simplified; no re-configuration is required at existing sites.

The clear demarcation of functionality between service provider and customer makes troubleshooting easier.

All of the above.

config>service# epipe service-id enable

config>service# vpws service-id enable

config>service# service-id no shutdown

config>port# port-id no shutdown

config>service# epipe service-id no shutdown

The MPLS TTL values are incremented at each request.

The router uses MPLS Echo Request packets that are IP-routed.

The router collects hop information along the tunnel's path.

The router performs an unidirectional LSP test.

config>service# epipe service-id shutdown

config>service# vpws service-id shutdown

config>service# service-id shutdown

config>port# port-id shutdown.

config>service# epipe service-id disable

There is no such calculation in IS-IS

Show router isis database

Show router isis dijykstra

Show router isis spf

Router R1 generates a type 5 LSA that is flooded through all OSPF areas.

Router R1 generates a type 7 LSA that is flooded through all OSPF areas.

Router R1 generates a type 5 LSA that is flooded through area 1. Router R2 generates a type 7 LSA that is flooded through areas 0 and 2.

Router R1 generates a type 7 LSA that is flooded through area 1. Router R3 generates a type 5 LSA that is flooded through areas 0 and 2.

None

1

2

3

4

Static route 2.3.4.0 255.255.255.0 next hop 3.4.5.6

Static-route next-hop 3.4.5.6 2.3.4.0/24

Static route 2.3.4.0/24 next hop 3.4.5.6

Static-route 2.3.4.0/24 next-hop 3.4.5.6

Area 1 of router R1 should not be configured as a stub.

Router R3 has the incorrect authentication key type.

Router R1 has the incorrect authentication key type.

There is not enough information to tell.

Hellos, CSNPs, PSNPs

LSPs. Hellos, CSNPs

LSPs, PSNPs, Hellos

LSPs, CSNPs, PSNPs

IPv4 In-Band Management

IPv6 Routing

IPv4 Multicast Routing

IPv6 Multicast Routing

All of the above are MT topologies defined for IS-IS.

Hello, link state update, link state packet, link State acknowledgement, database description.

Link state update, link state refresh, link state acknowledgement, database description, notification.

Hello, link state refresh, link state update, link state acknowledgement, link state authentication.

Hello, link state update, link state request, link state acknowledgement, database description.

Priority of 0

Priority of 1

Priority of 64

Priority of 255

The age for newly created link state information is set to 0 for OSPF and 1200 for IS-IS

The age for newly created link state information is set to 1200 for OSPF and 0 for IS-IS

The age is incremented or decremented as it is flooded from router to router and as it is held in the topological database.

The age is incremented or decremented only as it is held in the topological database and not as it is flooded router to router.

RIPv2 supports basic and MD5 authentication only.

RIPv2 supports password and MD5 authentication only.

RIPv2 does not support authentication, password and MD5 authentication.

RIPv2 does not support authentication.

1

49

83

0

Area ID

Hello and Dead Intervals

Stub flag

DR and BDR addresses

The list of neighbors

The protocol field of the transport layer header

The port field of the transport layer header

The protocol field of the network layer header

The port field of the network layer address

show router route-table

show router Idp bindings

show service service-using

show service egress-label

show router rsvp session