Q1. On which three options can Cisco PfR base its traffic routing? (Choose three.)
A. Time of day
B. An access list with permit or deny statements
C. Load-balancing requirements
D. Network performance
E. User-defined link capacity thresholds
F. Router IOS version
Answer: C,D,E
Explanation:
Key Advantages of using PfR for Load balancing:
. Utilization based load-balancing: PfR takes real-time link utilization into account when load balancing the links. This will ensure that a link will not go beyond a certain percentage of its maximum capacity (75% by default).
. Application Performance based Load Balancing: PfR does not randomly forward traffic through one link or another. It takes application performance requirements into consideration and then forwards the traffic through a link which meets the performance policy requirements. PfR also load balances the link at the same time.
. Bi-directional Solution: PfR is a bi-directional load balancing solution which influences outbound as well as in-bound traffic.
. Consolidated Centralized View: PfR offers consolidated and centralized view of the state of all external links in the network. At any given time, the network administrator can see the current link utilization (in kbps and percentage of its capacity), maximum link threshold, and the policies applied to the links in the network.
Reference: http://docwiki.cisco.com/wiki/PfR:Solutions:InternetOutboundLoadBalancing
Q2. Which BGP feature enables you to install a backup path in the forwarding table?
A. soft reconfiguration
B. prefix independent convergence
C. route refresh
D. synchronization
Answer: B
Explanation:
To install a backup path into the forwarding table and provide prefix independent convergence (PIC) in case of a PE-CE link failure, use the additional-paths install backup command in an appropriate address family configuration mode. To prevent installing the backup path, use the no form of this command. To disable prefix independent convergence, use the disable keyword.
Reference: http://www.cisco.com/c/en/us/td/docs/routers/crs/software/crs_r4-2/routing/command/reference/b_routing_cr42crs/b_routing_cr42crs_chapter_01.html
Q3. Which two statements about Cisco Express Forwarding are true? (Choose two.)
A. Cisco Express Forwarding tables contain reachability information and adjacency tables contain forwarding information.
B. Cisco Express Forwarding tables contain forwarding information and adjacency tables contain reachability information.
C. Changing MAC header rewrite strings requires cache validation.
D. Adjacency tables and Cisco Express Forwarding tables can be built separately.
E. Adjacency tables and Cisco Express Forwarding tables require packet process-switching.
Answer: A,D
Explanation:
Main Components of CEF
Information conventionally stored in a route cache is stored in several data structures for Cisco Express Forwarding switching. The data structures provide optimized lookup for efficient packet forwarding. The two main components of Cisco Express Forwarding operation are the forwarding information base (FIB) and the adjacency tables. The FIB is conceptually similar to a routing table or information base. A router uses this lookup table to make destination-based switching decisions during Cisco Express Forwarding operation. The FIB is updated when changes occur in the network and contains all routes known at the time. Adjacency tables maintain Layer 2 next-hop addresses for all FIB entries. This separation of the reachability information (in the Cisco Express Forwarding table) and the forwarding information (in the adjacency table), provides a number of benefits:
. The adjacency table can be built separately from the Cisco Express Forwarding table, allowing both to be built without any packets being process-switched.
. The MAC header rewrite used to forward a packet is not stored in cache entries, so changes in a MAC header rewrite string do not require validation of cache entries.
Reference: http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipswitch_cef/configuration/15-mt/isw-cef-15-mt-book/isw-cef-overview.html
Q4. Refer to the exhibit.
Which two actions can you take to enable CE-1 at site A to access the Internet? (Choose two.)
A. Create a default route for site A on PE-1 with the next hop set to the PE-2 interface to the Internet.
B. Originate a default route in site B with the next hop set to the PE-2 Internet interface, and import the default route into site A.
C. Create a default route on CE-1 with the next hop set to the PE-1 upstream interface.
D. Originate a default route in site A with the next hop set to the PE-2 interface to CE-1.
E. Create a static default route on CE-1 with the next hop set to the PE-2 interface to the Internet.
Answer: A,B
Q5. Consider a network that mixes link bandwidths from 128 kb/s to 40 Gb/s. Which value should be set for the OSPF reference bandwidth?
A. Set a value of 128.
B. Set a value of 40000.
C. Set a manual OSPF cost on each interface.
D. Use the default value.
E. Set a value of 40000000.
F. Set a value of 65535.
Answer: C
Explanation:
Unlike the metric in RIP which is determined by hop count and EIGRP’s crazy mathematical formulated metric, OSPF is a little more simple. The default formula to calculate the cost for the OSPF metric is (10^8/BW). By default the metrics reference cost is 100Mbps, so any link that is 100Mbps will have a metric of 1. a T1 interface will have a metric of 64 so in this case if a router is trying to get to a FastEthernet network on a router that is through a T1 the metric would be 65 (64 +1). You do however have the ability to statically specify a metric on a per interface basis by using the ip ospf cost # where the cost is an integer between 1-65535.
So the big question is why would you want to statically configure a metric? The biggest advantage of statically configuring an OSPF metric on an interface is to manipulate which route will be chosen dynamically via OSPF. In a nut shell it’s like statically configuring a dynamic protocol to use a specific route. It should also be used when the interface bandwidths vary greatly (some very low bandwidth interfaces and some very high speed interfaces on the same router).
Q6. Which two descriptions of the keying mechanisms that are used to distribute the session keys used in routing authentication are true? (Choose two.)
A. Peer keying creates a unique one-to-one relationship with another peer.
B. Group keying creates a single keying message to multiple peers.
C. Peer keying creates a single keying message to multiple peers.
D. Group keying creates a unique one-to-one relationship with another peer.
E. Group keying creates a full mesh of keying sessions to all devices.
F. Peer keying creates a full mesh of keying sessions to all devices.
Answer: A,B
Q7. How many address families can a single OSPFv3 instance support?
A. 1
B. 2
C. 5
D. 10
Answer: A
Q8. Which two statements about class maps are true? (Choose two.)
A. As many as eight DSCP values can be included in a match dscp statement.
B. The default parameter on a class map with more than one match command is match-any.
C. The match class command can nest a class map within another class map.
D. A policy map can be used to designate a protocol within a class map.
Answer: A,C
Explanation:
Answer A.
Router(config-cmap)# match [ip] dscp dscp-value [dscp-value dscp-value dscp-value
dscp-value dscp-value dscp-value dscp-value]
(Optional) Identifies a specific IP differentiated service code point (DSCP) value as a match criterion. Up to eight DSCP values can be included in one match statement.
Answer C.
Router config-cmap)# match class-map class-name (Optional) Specifies the name of a traffic class to be used as a matching criterion (for nesting traffic class [nested class maps] within one another).
Reference: http://www.cisco.com/c/en/us/td/docs/ios/12_2/qos/configuration/guide/fqos_c/qcfmcli2.html
Q9. What is the most efficient way to confirm whether microbursts of traffic are occurring?
A. Monitor the output traffic rate using the show interface command.
B. Monitor the output traffic rate using the show controllers command.
C. Check the CPU utilization of the router.
D. Sniff the traffic and plot the packet rate over time.
Answer: D
Explanation:
Micro-bursting is a phenomenon where rapid bursts of data packets are sent in quick succession, leading to periods of full line-rate transmission that can overflow packet buffers of the network stack, both in network endpoints and routers and switches inside the network. In order to troubleshoot microbursts, you need a packet sniffer that can capture traffic over a long period of time and allow you to analyze it in the form of a graph which displays the saturation points (packet rate during microbursts versus total available bandwidth). You can eventually trace it to the source causing the bursts (e.g. stock trading applications).
Reference: Adam, Paul (2014-07-12). All-in-One CCIE V5 Written Exam Guide (Kindle Locations 989-994). Kindle Edition.
Q10. Which technology is an application of MSDP, and provides load balancing and redundancy between the RPs?
A. static RP
B. PIM BSR
C. auto RP
D. anycast RP
Answer: D
Explanation:
Using Anycast RP is an implementation strategy that provides load sharing and redundancy in Protocol Independent Multicast sparse mode (PIM-SM) networks. Anycast RP allows two or more rendezvous points (RPs) to share the load for source registration and the ability to act as hot backup routers for each other. Multicast Source Discovery Protocol (MSDP) is the key protocol that makes Anycast RP possible.
Reference: www.cisco.com/c/en/us/td/docs/ios/solutions_docs/ip_multicast/White_papers/anycast.html