Answer: E 

Explanation: 

In the case of MPLS-VPN Backbone as The OSPF superbackbone behaves exactly like Area 0 in regular OSPF, so we cannot have two different area 0’s that are not directly connected to each other. When area 0 connects to the superbackbone, it simply becomes an extension of area 0. 

Answer: A 

Explanation: 

With route poisoning, when a router detects that one of its connected routes has failed, the router will poison the route by assigning an infinite metric to it and advertising it to neighbors. 

Answer: B,D 

Explanation: 

The RSTP does not have a separate topology change notification (TCN) BPDU. It uses the topology change (TC) flag to show the topology changes. 

Reference: http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst2950/software/release/12-1_9_ea1/configuration/guide/scg/swmstp.html 

Answer: C 

Explanation: 

Ideally, the Layer 2 device should forward the multicast transmission only out ports to which receivers are connected and also out any ports that are connected to downstream multicast routers. This configuration requires a Layer 2 device to be able to determine the ports on which multicast routers and receivers for each separate (S,G) or (*,G) multicast group are located. To facilitate intelligent forwarding of multicast traffic on the LAN, Cisco Catalyst switches support two mechanisms: 

. IGMP snooping — The switch listens in or "snoops" IGMP communications between receivers and multicast routers. This snooping enables the switch to determine which ports are connected to receivers for each multicast group and which ports are connected to multicast routers. 

. Cisco Group Management Protocol (CGMP) — The switch communicates with multicasts routers, with multicast routers relaying group membership information to switches. 

Reference: https://www.informit.com/library/content.aspx?b=CCNP_Studies_Switching&seqNum=59 

Answer: A,B 

Explanation: 

A transform set combines an encryption method and an authentication method. During the IPsec security association negotiation with ISAKMP, the peers agree to use a particular transform set to protect a particular data flow. The transform set must be the same for both peers. Also, the crypto map on R2 points to the address name of VPN, which includes 172.16.0.0/16, but it should be the local subnet of 192.168.0.0/16 

Answer: A 

Explanation: 

Sometimes it is desirable for a router to be configured so that it is not eligible to become the DR or BDR. You can do this by setting the OSPF priority to zero with the ip ospf priority priority# interface subcommand. If two OSPF neighbors both have their OSPF interface priority set to zero, they establish two-way adjacency instead of full adjacency. 

Reference: http://www.cisco.com/c/en/us/support/docs/ip/open-shortest-path-first-ospf/13683-11.html 

Answer: D 

Explanation: 

Silly window syndrome is a problem in computer networking caused by poorly implemented TCP flow control. A serious problem can arise in the sliding window operation when the sending application program creates data slowly, the receiving application program consumes data slowly, or both. If a server with this problem is unable to process all incoming data, it requests that its clients reduce the amount of data they send at a time (the window setting on a TCP packet). If the server continues to be unable to process all incoming data, the window becomes smaller and smaller, sometimes to the point that the data transmitted is smaller than the packet header, making data transmission extremely inefficient. The name of this problem is due to the window size shrinking to a "silly" value. When there is no synchronization between the sender and receiver regarding capacity of the flow of data or the size of the packet, the window syndrome problem is created. When the silly window syndrome is created by the sender, Nagle's algorithm is used. Nagle's solution requires that the sender sends the first segment even if it is a small one, then that it waits until an ACK is received or a maximum sized segment (MSS) is accumulated. 

Reference: http://en.wikipedia.org/wiki/Silly_window_syndrome 

Answer:  

Answer: A,D 

Explanation: 

Protected Ports (PVLAN Edge) In some network environments, there is a requirement for no traffic to be seen or forwarded between host(s) on the same LAN segment, thereby preventing interhost communications. The PVLAN edge feature provisions this isolation by creating a firewall-like barrier, thereby blocking any unicast, broadcast, or multicast traffic among the protected ports on the switch. Note that the significance of the protected port feature is limited to the local switch, and there is no provision in the PVLAN edge feature to isolate traffic between two "protected" ports located on different switches. For this purpose, the PVLAN feature can be used. 

Reference: http://www.ciscopress.com/articles/article.asp?p=1181682&seqNum=2 

Answer: A,B