350-001 Written

Front 1

Which types of prefixes will a router running BGP most likely advertise to an iBGP peer, assuming it is not a route reflector.

Back 1

prefixes received from ebgp peers and prefixes locally originated via network statements or redistributed

Front 2

You have two ebgp peers connected via two parallel serial lines. What should you do to be able to load balance between two ebgp speakers over the parallel serial lines in both directions?

Back 2

peer between the ebgp speakers loopbacks, configure multihop, and use an IGP to load-share between the two equal-cost paths between loopbacks

Front 3

What types of prefixes will a router running bgp advertise to an ebgp peer

Back 3

prefixes received from any other bgp peer and prefixes locally originated via network statements or redistributed to bgp

Front 4

How can a unidirectional link cause a loop?

Back 4

When no bpdus are received on a blocking port, the port waits for the max_age timer to expire, then transitions to the listening state. After waiting two times the forward_delay, the port transitions to forwarding and creates a loop.

Front 5

What does loop guard do?

Back 5

when bpdus are no longer received on a blocking port, loop guard places the port into a loop-inconsistent state to prevent a loop from forming

Front 6

Where should loop guard be configured?

Back 6

Loop guard must be enabled on the non-designated ports (more precisely, on root and alternate ports) for all possible combinations of active topologies

Front 7

How often are PIM join messages sent and why?

Back 7

pim join messages are sent every 60 seconds to refresh the upstream router's mroute state for the multicast state

Front 8

What does the ip pim autorp listener command do?

Back 8

Allows Auto-RP packets in groups 224.0.1.39 and 224.0.1.40 to be flooded in dense mode out interfaces configured with the ip pim sparse-mode command

Front 9

What is MSDP?

Back 9

MSDP is a mechanism to connect multiple Protocol Independent Multicast sparse mode (PIM-SM) domains. MSDP allows multicast sources for a group to be known to all rendezvous points (RPs) in different domains. Each PIM-SM domain uses its own RPs and need not depend on RPs in other domains. An RP runs MSDP over TCP to discover multicast sources in other domains.

Front 10

What is the RPT?

Back 10

The RPT is a unidirectional path from RP to Receiver

Front 11

What is the SPT?

Back 11

The SPT is a path built between the DR and the RP.

Front 12

How is the SPT built?

Back 12

1. Source goes active, sending out multicast packets on the LAN to which it is attached.
2. DR encapsulates the packets in a PIM REGISTER message sends it to the RP.
3. RP sends back a PIM JOIN message.
4. DR sends traffic down the SPT towards the RP.
5. RP sends a REGISTER-STOP message to the DR.
6. RP sends multicast traffic down the RPT towards the receiver

Front 13

What happens when an RP with MSDP peers receives a PIM REGISTER message?

Back 13

1. RP sends back a PIM JOIN message to DR.
2. Reencapsulates original packet into a Source-Active (SA) message, which identifies the source and group, as well as the IP address of the RP.
3. Sends SA message to all MSDP peers.
4. If the MSDP peer is an RP and has a member of that multicast group, the data packet is decapsulated and forwarded down the shared-tree in the remote domain.
5. Each MSDP peer receives and forwards the SA message away from the originating RP to achieve peer-RPF flooding.

Front 14

What is peer-RPF flooding?

Back 14

The concept of peer-RPF flooding is with respect to forwarding SA messages. The router examines the BGP or MBGP routing table to determine which peer is the next hop toward the originating RP of the SA message. Such a peer is called an "RPF peer" (Reverse Path Forwarding peer). The router forwards the message to all MSDP peers other than the RPF peer.

Front 15

What does Unicast RPF strict mode require in order to transmit a packet?

Back 15

That the packet was received on the same interface the router would use to reach the source.

Front 16

What does Unicast RPF loose mode require in order to transmit a packet?

Back 16

That the source address must appear in the routing table.

Front 17

GLBP allows how many MAC addresses assigned to the same default gateway virtual IP address?

Back 17

4

Front 18

Which three states does RSTP use?

Back 18

Learning
Forwarding
Discarding

Front 19

How are multicast MAC addresses determined?

Back 19

The last 23 bits of the multicast IP address is prepended by 0100.5e

Front 20

What is a Two-rate, three-color marker? How is it configured?

Back 20

This is a common policer configuration:

policy-map QOS_POLICER
class POLICED_TRAFFIC
police cir 512000 pir 1024000
conform-action transmit
exceed-action set-dscp-transmit
violate-action drop

Front 21

What is the encryption algorithm used for the priv option when using SNMPv3

Back 21

CBC-DES

Front 22

Which RMON group stores stats for conversations between sets of two addresses?

Back 22

matrix

Front 23

TFTP port assignment and message exchange

Back 23

Server: 10.0.0.1:69 RRQ/WRQ Received
Client: 10.0.0.2:1888 RRQ/WRQ Sent

Front 24

What is the default max reservable bandwidth by any single flow on an interface after enabling RSVP?

Back 24

75%

Front 25

Which two protocols can have their headers compressed through MQC?

Back 25

TCP
RTP

Front 26

What is the rule of synchronization?

Back 26

A BGP router can only advertise an iBGP learned route if the route is an IGP route in the routing table.

Front 27

What are the mandatory, well-known BGP attributes?

Back 27

origin
AS-path
next-hop

Front 28

If you connect ports 1/1 and 1/2 together on the same switch, what will happen (assuming portfast is not configured)

Back 28

Port 1/2 will be placed in blocking mode, as port priority is based on lowest port priority and lowest port ID.

Front 29

What keywords do you need to ad to the access-list to log source IP and MAC addresses?

Back 29

... log-input

Front 30

When using OSPF Graceful Restart in an NSF environment, which mechanism is used to continue forwarding packets during a switchover?

Back 30

Hardware-based forwarding

Front 31

What does it mean if the stack bit in an MPLS label is set to 1?

Back 31

The label is the last entry in the label stack

Front 32

Source Specific Multicast is best suited for applications that are in the ___ category.

Back 32

one-to-many

Front 33

What will happen if you enable IP Source Guard on an untrusted switch port that does not have DHCP snooping enabled?

Back 33

The DHCP server reply will be dropped and the client will not be able to obtain an IP address.

Front 34

Traffic with EF PHB should be marked with what DSCP value?

Back 34

46

Front 35

Frame Relay FECN messages are sent or received by whom?

Back 35

FECN messages are received by the destination. The destination then sends a BECN back to the sender to inform about the congestion experienced along the path.

Front 36

IPv6 multicast uses:

Back 36

MLD (Multicast Listener Discovery)

Front 37

If you have two overlapping ip address ranges, what commands are needed to globally configure NAT to get this to work?

Back 37

ip nat outside source static x.x.x.x y.y.y.y
ip nat inside source static x.x.x.x y.y.y.y

Front 38

What does a VTPv1 switch in Transparent mode do with received VTP advertisements?

Back 38

Discards them

Front 39

Phase I and Phase II DMVPN difer in terms of:

Back 39

Utilization of spoke-to-spoke dynamic tunnels

Front 40

PBR allows routing protocols to allow or deny paths based on:

Back 40

End system
Protocol
Application

Front 41

By default, an ABR will inject a default route into which types of areas?

Back 41

Stub
Totally Stubby

Front 42

What is the mathematical relationship between committed information rate, committed burst, and committed rate interval?

Back 42

Tc=Bc/CIR

Front 43

What are the 802.1w port roles?

Back 43

Root
Designated
Alternate
Backup
Disabled

Front 44

What does the STP root guard feature prevent?

Back 44

Root guard prevents a port from becoming a root port.

Front 45

EIGRP Default Metric

Back 45

256*(10^7/BW+Delay/10)

Front 46

What type of queuing does the CBWFQ class-default queue support?

Back 46

WFQ

Front 47

The CBWFQ scheduler provides a guaranteed __ to each class.

Back 47

minimum amount of bandwidth

Front 48

When calculating the round-trip delay in IP SLA operations, the processing time on the end routers is only assessed for operations that involve __

Back 48

the responder

Front 49

In order to avoid a spanning tree loop when configuring a static etherchannel, what two steps should be taken?

Back 49

Disable all interfaces;
Configure the EC as "desirable" before configuring as "on"

Front 50

What mechanism can you use to achieve sub-second failover for link failure detection when a switched ethernet media is used and loss of signal is not supported by the link provider?

Back 50

Bidirectional Forwarding Detection

Front 51

Shaped round robin does not support what type of queuing?

Back 51

Strict priority

Front 52

When configuring EIGRP over DMVPN, what relevant commands should you configure on the hub?

Back 52

disableeigrp as-member split-horizon
disableeigrp as-member next-hop-self

Front 53

Under what two circumstances would an RSTP bridge flush its CAM table?

Back 53

Upon receiving a TCN
When transitioning from discarding to forwarding

Front 54

Does NBAR support multicast?

Back 54

No