CCIE Recertification Question of the Week - DEC1506

From: anthony.sequeira@thomson.com
Date: Thu Dec 14 2006 - 17:13:12 ART


IMPORTANT NOTE! A new version (3.0) of the CCIE-R/S Written Exam will
release between January 17th and January 19th of 2007. The moment the
new exam releases, NetMasterClass will enable version 3.0 of TESTiT for
the new exam! This new version will (as always) map to every objective
of the new written exam blueprint.

LAST WEEK'S ANSWER:

Answer: d

Topic Domain: 3e

Issues:

What is the error in this configuration?

Solutions:

Here the issue is with the static route. At this point R1 does not have
enough information to encapsulate IPv6 packets using the 6to4 scheme. It
has a configured IPv4 tunnel source 172.16.101.1, but it does not know
what IPv4 address should be used for the tunnel destination. The IPv4
address is derived from R2's tunnel address (2002:AC10:6601::/128).
Embedded in this address is the IPv4 address 172.16.102.1. Therefore,
you have to create a static route to 24::/64 not via the tunnel
interface but via the next hop IPv6 address 2002:AC10:6601::. Networks
that are reachable via 6to4 IPv6 tunnels must be listed in the routing
table with the 6to4-like next hop IPv6 address. You should note that
this is not fully documented in the More Information link provided!

More Information:

Configuring 6to4 Tunnels

http://www.cisco.com/univercd/cc/td/doc/product/software/ios123/123cgcr/
ipv6_c/sa_tunv6.htm#wp1037465

LAST WEEK'S QUESTION:

3-10-1. You have made the partial configuration shown in Exhibit 1. You
are on a client PC configured with R1 as the default gateway and you are
trying to ping a destination in the 24::/64 network. The ping is not
successful. What is the most likely problem?

a. There are no tunnel destinations configured for the tunnel
endpoints

b. The tunnel endpoints must be configured with IPv4 addresses
and IPv6 tunnel source addresses

c. This tunnel mode has been deprecated and is no longer
supported on a Cisco router

d. The static route should point to the IPv6 next hop address of
the tunnel endpoint

e. This tunnel mode cannot be configured for intrasite
connectivity

Exhibit 1

R1:

interface Tunnel12

 no ip address

ipv6 address 2002:AC10:6501::/128

 tunnel source 172.16.101.1

 tunnel mode ipv6ip 6to4

!

ipv6 route 24::/64 tunnel 12

R2:

interface Tunnel12

 no ip address

ipv6 address 2002:AC10:6601::/128

 tunnel source 172.16.102.1

 tunnel mode ipv6ip 6to4

THIS WEEK'S QUESTION:

4-7-1. You have the topology shown in Exhibit 1 and the configuration
shown in Exhibit 2. Which statements are true regarding the 10.2.0.0
route? Choose all that apply.

a. The route should appear on R1

b. The route should appear on R2

c. The route should appear on R3

d. None of these options are correct

Exhibit 1

(R1-AS64600)<----->(R2-AS64700)<----->(R3-AS64800)

Exhibit 2

R1

router bgp 64600

network 10.1.0.0 mask 255.255.0.0

network 10.2.0.0 mask 255.255.0.0

network 10.3.0.0 mask 255.255.0.0

network 10.4.0.0 mask 255.255.0.0

neighbor 172.16.1.2 remote-as 64700

neighbor 172.16.1.2 route-map SETCOMM out

!

access-list 1 permit 10.2.0.0 0.0.255.255

!

route-map SETCOMM permit 10

match ip address 1

set community no-export

route-map SETCOMM permit 20

Question of the Week Compliments of:

TESTiT

http://www.netmasterclass.com/site/written.php



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