Question | Answer |
What routing type periodically passes entire routing tables? | Distance Vector |
What routing type floods updates within the area? | Link State |
EIGRP uses what type of routing? | Hybrid |
BGP uses what type of routing? | Path Vector |
What timer marks a route as unreachable if an updates is not received over so many intervals? | Invalidation Timer |
This limit is set for Distance Vector routing to prevent 'counting to infinity' | Hop Count |
When a metric worsens, this timer disallows updates for a delay period | Hold-down Timer |
Asynchronous updates use this timer to prevent router synchronization | Random Delay Timer |
Setting the metric to 'unreachable' | Route Poisoning |
This rule says do no send updates out of the interface on which that update was received | Split-Horizon |
This protocol doesn't automatically turn off Split-Horizon on frame-relay hub and spoke environments | EIGRP |
An exception to the split horizon rule to influence sender of route update | Poison Reverse |
Another name for Summarization | Aggregation |
What is the purpose of a static route to NULL0 with summary advertisements | This is a loop prevention mechanism to drop packets that are destined to a part of the summary route that the router doesn't know how to reach |
Which routing protocols auto-summarize by default? | RIP and EIGRP |
What are the three main routing decision criteria? | Prefix Length, Administrative Distance, Metric |
Admin Distance of Directly Connected Route? | 0 |
Admin Distance of Static Route? | 1 |
Admin Distance of EIGRP Summary Route? | 5 |
Admin Distance of External BGP Route? | 20 |
Admin Distance of Internal EIGRP Route? | 90 |
Admin Distance of IGRP Route? | 100 |
Admin Distance of OSPF Route? | 110 |
Admin Distance of IS-IS Route? | 115 |
Admin Distance of RIP Route? | 120 |
Admin Distance of ODR Route? | 160 |
Admin Distance of External EIGRP Route? | 170 |
Admin Distance of Internal BGP Route? | 200 |
Admin Distance of Unknown Route? | 255 |
A copy of the routing table is cached in memory inside this structure | Forwarding Information Base (FIB) |
A copy of the mac address-table is cached in memory inside this structure | Adjacency Table |
Negative effect of redistribution | Information is lost |
Where is redistribution performed? | On border routers running more than one routing protocol |
When an area is a path between two other routing domains, it is also know as a ____________ . | Transit Routing Domain |
These routing domains don't carry transit packets | Stub |
Routing instability due to 'feedback' causes __________. | Routing Loops |
Three ways to troubleshoot routing loops | Admin Distance, Route Filtering, and More Careful Redistribution |
What is the 'Split-Horizon' rule with redistribution? | Never redistribute a prefix into a domain and then accept the same prefix from another domain |
3 Unicast Flooding Causes | Asymmetric Routing, STP Topology Changes, MAC Table Overflow |
4 Steps of 802.1D Election Process | Elect the root bridge, Select root ports on all non-root bridges, Select designated ports per link, Block all other ports |
How is the root bridge elected? | Switches examine Bridge ID, lowest value wins |
What does the Bridge ID consist of? | 2 Byte Priority, 6 Byte Mac Address, VLAN ID mapped to 12 lower order bits of Priority field |
How is priority adjusted to accommodate VLAN ID? | In increments of 4096 |
What is the default priority? | 32768 |
Two ways to set priority? | With a macro (primary or secondary) or direct numeric value |
Every port on the root bridge is a __________. | designated port |
What are the 3 steps of the STP tiebreaking process on a designated port? | Lowest path cost to root bridge, lowest sender Bridge ID, Lowest Port ID |
4 STP Port States in order of occurrence | Block, Listening, Learning, Forwarding |
802.1d blocking timer, name and length? | max-age,' 20 seconds |
802.1d listening timer name and length? | forward delay,' 15 seconds |
802.1d learning timer name and length | forward delay,' 15 seconds |
802.1d enhancement for access layer switches | UplinkFast |
802.1d enhancement for entire topology | BackboneFast |
What will UplinkFast manipulate for redundancy | Bridge priority value |
How does BackboneFast benefit convergence? | Skips the blocking stage 'max-age' |
Lowest possible Root Bridge ID | 0 |
Recommended bridge priority for backup root | 8192 |
UplinkFast default priority | 49152 |
Default STP Extended System ID | 4107 |
3 Port States of 802.1w | Discarding, Learning, and Forwarding |
4 Port Roles of 802.1w | Root Port, Designated Port, Alternate Port, Backup Port |
802.1w Alternate Port is backup to what? | Root Port |
802.1w Backup Port is backup to what? | Designated port |
802.1w replaces simple use of timers with what? | Proposal and Agreement process |
How are BPDUs different in 802.1w? | It carries more information and is also used as a keepalive mechanism |
In 802.1w, how are edge ports different from point-to-point ports? | TCNs are not sent when edge ports go down |
How is the origin of TCNs different in 802.1w than 802.1d? | TCNs are originated on the bridge where the change occurs as opposed to just from the root bridge |
What is the default instance for MST? | 0 |
3 important steps for 802.s configuration | Region Name, Revision Number, VLAN to Instance Mappings |
This STP Protection Mechanism prevents against hardware or software failures | LoopGuard |
This STP Protection Mechanism prevents against fiber optic problems | UDLD |
This STP Prevention mechanism enforces the STP domain borders and keeps the active topology predictable | BPDUGuard |
This STP Prevention mechanism enforces the Layer 2 STP topology | RootGuard |
This STP Prevention mechanism stops BPDUs from being sent on a port and also ignores received BPDUs | BPDUFilter |
This L2 prevention mechanism monitors traffic by traffic type in 1 second intervals | Storm Control |
Which trunk modes don't send DTP frames? | off, auto, nonegotiate |
Which trunk modes send DTP frames? | on, desirable |
3 modes of VTP? | Server, Client, Transparent |
This VTP mode only learns its database from server | Client |
This VTP mode is the default | Server |
This VTP mode ignores, but forwards messages | Transparent |
What percent of errors are acceptable when running in half-duplex mode? | 1% |
What types of errors are expected in Half Duplex mode? | FCS, Alignment, Runts, and Collisions |
This OSPF router type has all interfaces in one area | Internal Router |
This OSPF router type has at least one interface in area 0 | Backbone Router |
This OSPF router type is connected to at least two different areas | Area Border Router (ABR) |
This OSPF router type has at least one interface in an area and at least one other interface in another autonomous system | Autonomous System Boundary Router (ASBR) |
Name of LSA Type 1? | Router LSA |
Name of LSA Type 2? | Network LSA |
Name of LSA Type 3? | Network Summary LSA |
Name of LSA Type 4? | ASBR Summary LSA |
Name of LSA Type 5? | AS External LSA |
Name of LSA Type 7? | NSSA External LSA |
This LSA is generated by every router in the area | Router LSA |
This LSA is generated by the DR | Network LSA |
This LSA is generated by ABRs | Network Summary LSA |
This LSA is generated by ABRs to advertise the ASBR | ASBR Summary LSA |
This LSA is generate by the ASBR | AS External LSA |
This LSA is generated by the ASBR in a NSSA area | NSSA External LSA |
Where are Type 1 LSAs flooded? | In the area of origination |
Where are Type 2 LSAs flooded? | In the area of origination |
Where are Type 3 LSAs flooded? | Throughout the AS |
Where are type 4 LSAs flooded? | Throughout the AS |
Where are Type 5 LSAs flooded? | Throughout the AS |
Where are Type 7 LSAs flooded? | In the area of origination |
What is the OSPF Backbone Area responsible for? | Summarization of each area to every other area |
3 design rules of OSPF Backbone Area? | Must be area 0, must be contiguous, every non-area 0 must touch area 0 |
Which LSA types are blocked by a stub area? | 4 and 5 |
Which LSA types are blocked by a totally stubby area? | 3,4, and 5 |
Which stub area type doesn't have a default route injected by the ABR? | NSSA |
This area allows external prefixes from the area ASBR, but restricts other external routes | Totally NSSA |
OSPF interface command to summarize from one area to another | area range |
OSPF interface command to summarize from another domain into OSPF | summary-address |
Name the 7 OSPF network types | point-to-point, point-to-multipoint, point-to-multipoint non-broadcast, broadcast, non-broadcast multi-access, virtual-links, loopback |
These 2 OSPF network types don't use a DR or BDR, but uses neighbor discovery | point-to-point, point-to-multipoint |
This OSPF network type doesn't use a DR or BDR, but neighbors have to be manually configured | point-to-multipoint non-broadcast |
This OSPF network type uses a DR/BDR and uses neighbor discovery | broadcast |
This OSPF network type uses a DR/BDR , but neighbors have to be manually configured | NBMA |
This OSPF network advertises its prefix as a host route | Loopback |
This OSPF feature prevents domain disruptions while processes are restarting | Graceful Restart |
If there is an incorrect OSPF network type configuration or misconfigured interfaces, what problem would this cause? | neighbor list empty |
If there is a secondary IP address issue or Layer1/Layer2 problem in OSPF, what could this cause? | neighbor list empty |
If an ACL is blocking or there is a stub flag mismatch, what problem could this cause in OSPF? | neighbor list empty |
If there is a Layer3 interface configuration error or area ID mismatch in OSPF, what problem could this cause? | neighbor list empty |
If there is a timer mismatch or authentication error in OSPF, what problem could this cause? | neighbor list empty |
If a neighbor statement is misconfigured or unicast doesn't work in the NBMA environment, what OSPF problem could this cause? | Stuck in Attempt state |
If hellos are being blocked in one direction or the broadcast keyword is missing from the frame-relay map command in OSPF, what problem could this cause? | Stuck in INIT state |
If multicast is nonfunctional on one side or there is only authentication on one side in OSPF, what problem could this cause? | Stuck in INIT state |
If all routers have a priority of 0 or there is broken unicast communication in OSPF, what problem could this cause? | Stuck in TWO-WAY state |
If a neighbor is stuck in EXSTART or there are duplicate Router IDs in OSPF, what problem could this cause? | Stuck in TWO-WAY state |
What two problems could be presented by a MTU mismatch in OSPF? | Stuck in TWO-WAY state or stuck in LOADING |
If there is a corrupted link-state request or a MTU mismatch in OSPF, what problem could this cause? | Stuck in LOADING state |
Which protocol and port number does BGP use? | TCP 179 |
eBGP peers are assumed to be ________________. | directly connected |
What are the 3 solutions for the 'iBGP Split-Horizon' rule? | Route Reflector, Confederations, or Fully Meshed Peers |
What two commands are necessary on a confederation border router? | bgp confederation identifier and bgp confederation peers |
What are the 5 components of the EIGRP metric? | Bandwidth, Delay, Load, Reliability, and MTU |
The name for the EIGRP cost between the local router and the destination prefix | Feasible Distance |
The name for the EIGRP cost that the next hop is advertising to the local router | Advertised Distance |
What the EIGRP feasibility check rule? | the AD of the next hop router must be less than the FD of the current successor |
What does the EIGRP status code Passive mean? | network available |
What does the EIGRP status code Active mean? | network unavailable |
What does the EIGRP status code Update mean? | network is being updated |
What does the EIGRP status code Query mean? | outstanding query |
What does the EIGRP status code Reply mean? | generating a reply to a query |
What does the EIGRP status code SIA mean? | convergence problem |
What are the two ways to limit the scope EIGRP queries? | stub or summarization |
What is an EIGRP SIA Query? | special query to make sure peer relationship is still valid |
What 5 parameters can you match traffic for policy routing? | protocol, application, source ip, destination ip, Layer 3 packet length |
What 3 parameters can you set for Policy Based Routing? | next-hop, output interface, default next-hop |
What advantage does PfR have over PBR? | It uses performance metrics |
What are the two core components of PfR? | Master Controller (MC) and Border Router (BR) |
What are the 5 phases of PfR | Profile, Measure, Apply, Control, and Verify |
This PfR phase identifies the traffic classes to control? | Profile |
In this PfR phase, BRs collect statistics and report them to the MC. | Measure |
What two ways can PfR measure traffic? | Passively or Actively |
In this PfR phase, acceptable thresholds of performance are defined. | Apply |
In this PfR phase, the MC uses BR reported information to identify classes or links that are Out Of Policy | Apply |
In this PfR phase, the MC controls routing protocol decision. | Control |
In this PfR phase, the MC ensures the changes have brought the network to In-Policy | Verify |
Where are the learned traffic classes stored during the PfR profile phase? | Monitored Traffic Classes table (MTC) |
How does PfR learn prefix traffic classes? | NetFlow Top talker feature |
How does PfR learn application traffic classes? | the 'protocol' command |
What 5 states are there in the PfR measure phase? | Default, Choose Exit, Hold-down, In-Policy, Out-of-Policy |
How is passive measuring done in PfR? | NetFlow |
How is active measuring down in PfR? | IP SLA |
How can the apply phase ensure that the network is not unstable as a result of PfR? | Timers |
How are policies configured in PfR? | oer-map |
In what 3 ways are routing changes initiated in PfR? | a traffic class goes OOP, an exit link goes OOP, or a period timer expires and traffic classes are in 'choose exit' state |
In what 3 ways are routing changes actually made in PfR? | IGP metric change, BGP attribute change, route injection, or PBR |
What does the PfR verify phase rely on? | NetFlow |
Default HSRP Priority? | 100 |
How is the HSRP Active router selected? | Highest priority |
What port and type does HSRP use for hellos? | UDP, 1985 |
How to fix HSRP state changes on a multicast stub? | Put an access-list on the non-DR |
This GLBP router is responsible for responding to ARP requests with virtual MAC address | AVG |
Which GLBP load-balancing method is the default? | round-robin |
Which GLBP multicast address is used for hellos? | 224.0.0.102 |
How often are GLBP hellos sent? | Every 3 seconds |
Which port and type does GLBP use? | UDP, 3222 |
What GLBP router is only responsible for forwarding packets? | AVF |
How is the Virtual IP address of VRRP different from HSRP? | The Virtual IP of the Virtual Router Group is the same as the physical IP of the Virtual Route Master |
This NAT address is assigned to a host inside the network | Inside Local |
This NAT address is a non-private address that represents the inside host | Inside Global |
This NAT address is the IP address of an outside host as it appears in the inside network | Outside Local |
This NAT address is the IP address assigned to a host on the outside network | Outside Global |
Which NAT keyword specifies Port Address Translation (PAT) | overload |
What is the command to configure a router in NTP client mode? | ntp server X.X.X.X |
Command to update battery powered hardware clock? | ntp update-calendar |
Command to configure router as NTP server | ntp master [stratum] |
What is the default NTP stratum? | 8 |
What does NTP stratum 1 indicate? | That the router itself is the time source |
What NTP command is used to enable Symmetric Active Mode? | ntp peer X.X.X.X |
What NTP interface command is used to turn on broadcasts? | ntp broadcast version 2 |
Describe the DHCP 4-way handshake process | Host broadcasts discover, server unicasts OFFER, client unicasts REQUEST, server unicasts ACKNOWLEDGEMENT |
What are the 3 mandatory steps to configure a DHCP server? | Excluded Address, DHCP pool, and Network Address |
What are the two ways to create DHCP reserved addresses? | With the host command inside the pool or with the origin file command |
What is the default version of WCCP? | Version 2 |
What are the two main limitations of WCCP Version 1? | It can only do port 80 redirects, and can only have 1 router per Content Engine Cluster |
How many routers and Content Engines does WCCP Version 2 support? | 32 routers and 32 Content Engines |
If Multicast is used for WCCP communication, what are the two prerequisites? | All Content Engines in the cluster must be able to communicate with all routers and the routers have to have a TTL of 15 or less |
What are the two ways to redirect traffic in WCCP and when are they used? | GRE (if router and content engine not on same subnet) or direct Layer2 if they are |
How does WCCP handle L2 redirection? | By rewriting the MAC address |
Which WCCP interface command specifies what traffic to redirect? | ip wccp web-cache redirect in (on requester facing interface) or ip wccp web-cache redirect out (on internet facing interface) |
Command to globally enable WCCP? | ip wccp web-cache |
Command to limit WCCP Content Engines permitted to participate? Global or interface command? | ip wccp web-cache group-list N (global) |
Command to limit WCCP requesters? (global or interface) | ip wccp web-cache redirect list N (interface) |
Which IP version does WCCP support? | IPv4 only |
What does the command 'no logging on' do? | Forces messages to the console |
How to create custom syslog event? | event tag WORD |
How to specify timeframe for event in Embedded Event Manager? | trigger |
How to associate different events into one group in Embedded Event Manager? | correlate |
How to specify router response if trigger is activated? | action |
What three ways can IP SLA information be accessed? | CLI, SNMP, and Syslog |
Name the 10 normal IP SLA operation types. | UDP Jitter, ICMP Path Jitter, UDP Jitter for VoIP, UDP Echo, ICMP Echo, ICMP path Echo, HTTP, TCP Connect, FTP, DHCP |
Name the 2 legacy IP SLA operation types. | DLSW+ and Frame Relay |
What is the most commonly used IP SLA operation type? | UDP Jitter |
This IP SLA operation type measures RT delay, OW delay, OW jitter, OW packet loss, and connectivity. | UDP Jitter |
This IP SLA operation type measures hop by hop jitter, packet loss, and delay. | ICMP Path Jitter |
This IP SLA operation type measures RT delay, OW delay, OW jitter, OW packet loss. | UDP Jitter for VoIP |
This IP SLA operation type simulates various codecs and does voice quality scoring. | UDP Jitter for VoIP |
This IP SLA operation type measures round trip delay for UDP traffic. | UDP Echo |
This IP SLA operation type measures round trip delay for the full path. | ICMP Echo |
This IP SLA operation type measures round trip delay and hop by hop round trip delay. | ICMP Path Echo |
This IP SLA operation type measures round trip time for web page traffic. | HTTP |
This IP SLA operation type measures the time to establish a session with a target. | TCP Connect |
This IP SLA operation type measures the round trip time for file transfers. | FTP |
This IP SLA operation type measures the round trip time for address acquisition. | DHCP |
This IP SLA operation type measures the peer tunnel response time. | DLSW+ |
This IP SLA operation type measures circuit availability, RT delay, and the frame delivery ratio. | Frame Relay |
This IP SLA destination system runs on a Cisco router | IP SLA Responder |
What is the benefit of using an IP SLA Responder? | Eliminates processing delays on the source and the target |
What protocol is using for IP SLA Responder? | IP SLA Control Protocol |
IP SLA is a key ingredient in what Cisco feature? | OER / PfR |
What are the three steps of configuring the QOS MQC? | class-map, policy-map, service-policy |
What are the two functions of NBAR? | protocol analysis and traffic classification for QOS |
What is the name of NBAR definitions? | PDLMs |
What benefit does NBAR have over access-lists? | Deep packet inspection to the application layer |
Command to enable NBAR monitoring? | ip nbar protocol-discovery |
Layer 2 QoS marking? How many bits? | CoS, 3 |
Layer 3 QoS markings? How many bits? | ToS - IP Precedence (First 3 bits of byte) and DSCP (First 6 bits of byte) |
MPLS QoS marking? How many bits? | Experimental Bits or Traffic Class, 3 |
Frame-Relay QoS marking? How many bits? | DE, 1 |
ATM QoS marking? How many bits? | CLP, 1 |
What is the CoS 0 Application? | Best Effort (Routine) |
What is the CoS 01Application? | Medium Priority Data (Priority) |
What is the CoS 2 Application? | High Priority Data (Immediate) |
What is the CoS 3 Application? | Call Signaling (Flash) |
What is the CoS 4 Application? | Video (Flash-override) |
What is the CoS 5 Application? | Voice Bearer (Critical) |
What is the CoS 6 Application? | Reserved (Internet) |
What is the CoS 7 Application? | Reserved (Network) |
What are the last two bits of the IP ToS byte used for? | Flow Control |
What is the DSCP Class Selector PHB used for? | Pure backward compatibility with IP Precedence |
What is the DSCP Default PHB and bit value? | Best effort service (000 000) |
What is the DSCP Assured Forwarding PHB and initial bit values? | Guaranteed bandwidth services - 001, 010, 011, or 100 |
Describe the DSCP AF drop probabilities. | 010 - Low probability, 100 - Medium probability, 110 - High probability |
What is the DSCP EF PHB and bit value? | Voice, 101 110 |
How do the drop probability values differ between AF and EF? | In AF, 110 means high probability of drop - In EF, 110 means don't drop |
In what three ways can QoS Policy Propagation through BGP classify packets? | Access lists, BGP Community lists, and BGP AS Paths |
What problem does QoS Priority Queuing introduce? | Starvation |
What problem does QoS Custom Queuing introduce? | Latency for voice |
What problem does Weighted Fair Queuing introduce? | Can't accommodate bandwidth reservations |
What is the default behavior for full queues in CBWFQ? | Tail Drop |
What is the default processing behavior in each CBWFQ queue? | FIFO |
What three types of weighting can be used in CBWFQ? | Bandwidth, Bandwidth Percent, Remaining Bandwidth Percent |
How many types of weighting can you use in one QoS service policy? | 1 |
What percentage of interface bandwidth should not be assigned by CBWFQ? | 25% |
How is Low Latency Queuing different from CBWFQ? | It adds a priority queue |
How does Low Latency Queuing stop the priority queue from starving other queues? | the prioritized bandwidth is policed |
What is QoS Modified Deficit Round Robin? | Deficit Round Robin with a priority queue added |
What are the two modes of Modified Deficient Round Robin and how do they work? | Alternate - there will never be starvation, Strict priority - services the priority queue no matter what |
This congestion avoidance technique prevents global synchronization? | Random Early Detection (RED) |
What is the problem with Random Early Detection (RED)? | No way to differentiate what traffic to drop |
What is the default Weight Random Early Detection denominator? | 10 |
Explain the WRED min threshold. | Specifies at what level to start random drops |
Explain the WRED max threshold | Specifies at what level to start tail drop |
Explain the WRED max drop probability. | Specifies what percentage of packets will be dropped (1/N) |
Command to enable WRED and in what MQC mode? | random-detect, policy configuration mode |
What is the default ToS type that WRED uses to determine a traffic profile? | IP Precedence |
Explain 3 ways that policing and shaping are different? | Shaping can only be outbound, Shaping buffers excess traffic, Policing drops or re-marks traffic |
What is the policing token formula? | CIR = Bc / Tc |
What is Tc? | timing interval |
What is Bc? | normal burst size |
What are the three states of a Dual-Token, Single Rate Bucket? | Conforming, Exceeding, Violating |
What two rates are enforced on a Dual-Rate Token Bucket? | CIR and PIR |
What interfaces are supported for AutoQoS? | Physical Serial (HDLC and PPP), Frame-Relay P2P subinterfaces, and ATM P2P subinterfaces |
What is the interface speed limit for ATM subinterfaces? | less than 768k |
What is a requirement of AutoQoS for slow speed links? | It must be configured on both sides |
What is a requirement of AutoQoS for an ATM PVC? | a bit rate has to be set |
What 5 signaling protocols is AutoQoS built to identify? | H.323, H.225 (Unicast Only), SIP, 'Skinny', and MGCP |
"Where does the command ""auto qos voip"" go in a frame-relay environment?" | in dlci config mode |
What are the two phases of AutoQoS for Enterprise? | Discovery Phase, Installation Phase |
How is AutoQoS similar to AutoQoS for Enterprise? | Same set of restrictions |
Command to enable Phase 1 of AutoQoS for Enterprise? | auto discovery qos |
Command to enable Phase 2 of AutoQoS for Enterprise | auto qos |
Which frame relay DLCIs are reserved? | 0-15 and 1008-1023 |
How does the router know what LMI type to use? | auto-sense by trying each one |
What three LMI options are there? | Cisco, ANSI, Q.933 - Annex A |
What does the LMI status ACTIVE mean? | Healthy on each end and data can be transferred |
What does the LMI status INACTIVE mean? | local connection is healthy, but the remote side is not |
What does the LMI status DELETED mean? | No LMI, or the DLCI was deleted from the SP Frame-Relay switch |
What is the full mesh formula? | [n(n-1)]/2 |
Why was Phase II of DMVPN created? | to permit the dynamic creation of spoke-to-spoke tunnels |
What 3 technologies is used by DMVPN? | IPSec, Multipoint GRE (mGRE), and Next Hop Resolution Protocol (NHRP) |
This DMVPN technology is used to dynamically register addresses from the spokes | Next Hop Resolution Protocol (NHRP) |
This DMVPN technology is used to transport data and routing information from the hub to multiple (potential) spokes | mGRE |
Command to create DMVPN mGRE tunnel? | tunnel mode gre multipoint |
Commands to configure the two phases of IPSec | crypto isakmp policy and crypto ipsec transform |
Command to create an IPSec profile to | crypto ipsec profile |
What class and IPv4 range is reserved for multicast? | Class D, 224.0.0.0 - 239.255.255.255 |
What is the multicast Local Link Range reserved for? | Reserved for routing protocols and other maintenance functions |
What is the IPv4 multicast Local Link Range? | 224.0.0.0 - 224.0.0.255 (Local Network Control Block) |
What is the ipv4 multicast Internet Application Range? | Range is 224.0.1.0 - 224.0.1.255 (Internetwork Control Block) |
What is GLOP used for? | It is used for sourcing multicast content on the internet |
How is GLOP assigned? | 233.AS_Value.Local_Assignment |
What is the range of IPv4 multicast addresses that are administratively scoped for organizations? | 239.0.0.0 - 239.255.255.255 |
What are the top 256 addresses in each Admin Scope reserved for? | Scope Relative Address, such as 239.255.255.249 (reserved for DHCPv4) |
What is the disadvantage of IGMP Version 1 | Hosts have no way of notifying routers when they don't want the multicast stream |
What major improvement was made with IGMP Version 2? | Hosts now have the ability to send a 'Leave Group' message |
What is the benefit to IGMP Version 3 | It ads Source Specific Multicast (SSM) |
What three messages are used by IGMP hosts? | Membership Report, Version 1 Membership Report, Leave Group |
What two types of IGMP messages are used by routers? | General Query and Group-Specific Query |
Command to turn multicast routing on globally | ip multicast-routing |
Command to enable PIM on an interface | ip pim [sparse-mode | dense-mode| sparse-dense-mode] |
Command to verify IGMP operation on an interface | show ip igmp interface |
What is the PIM traffic forwarding concept? | Multicast traffic radiates away from a source rather than to a destination |
What are the two types of PIM trees? | Source-Based Tree and Shared Tree |
What does (S, G) mean? | Source-Based Tree where 'S' denotes class A,B, or C source IP address and 'G' denotes the multicast group address |
What does (*, G) mean? | Shared Tree where '*' denotes any source and 'G' denotes multicast group address |
What are the three modes of PIM? | Dense Mode, Sparse Mode, and Sparse-Dense Mode |
How often does PIM DM flood and prune? | Every 3 minutes |
Which PIM mode has an explicit join approach? | PIM Sparse Mode |
What is a negative effect of PIM DM? | Requires a lot of CPU overhead |
What is a negative effect of PIM SM? | May have increased delay |
What is necessary when multiple multicast routers are connect to a multi-access network? | A designated router |
How is the multicast Designated Router elected? | Highest IP address, Loopback, then other interfaces |
What is the function of the multicast Designated Router? | To send Join and Prune message to the RP |
Name the technology that is a variation on the PIM-SM mode introduced to address issues for groups with a large number of sources | Bidirectional PIM |
How does Bidirectional PIM forward traffic? | with (*,G) mechanisms only |
What are the two functions of the multicast designated Forwarder for Bidirectional PIM? | To prevent loops and forward appropriate multicast traffic upstream |
How is the multicast Bidirectional PIM Designated Forwarder elected? | Best Unicast route to the RP |
What does reverse path forwarding mean? | Moving traffic away from the source, instead of to a destination |
How does the RPF Check work? | It uses the unicast IP routing table to determine the upstream bath to the source and checks the interface that a multicast packet was received on |
What is the primary loop prevention mechanism in multicast? | RPF Check |
What are the three ways to fix an RPF failure? Which one is the best? | Run PIM DM over necessary links, Change the unicast routing table, or Create a Static Multicast Route |
Command for creating static multicast route | ip mroute (source ip) (network mask) (interface) |
What two methods exist for automatically assigning the Rendezvous Point? | Auto-RP and Bootstrap Router (BSR or PIM Version 2) |
What is the term for routers that want to be RPs? | Candidate RPs |
What is the flaw with Auto-RP? | It uses a dense multicast address to speak to clients to give them the RP (multicast) address (A problem in sparse mode only) |
What multicast address is used by Candidate RPs in Auto-RP? | 224.0.1.39 |
What multicast address is used by the mapping agent? | 224.0.1.40 |
Command to declare candidacy for RP? | ip pim send-rp-announce |
Command to announce Mapping Agent? | ip pim send-rp-discovery |
What are the two fixes for the SM problem with Auto-RP? | Statically assign the RP or use the 'ip pim auto rp listener' on each SM router |
What technology allows multiple RPs to load share and provide hot backups for each other? | Anycast RP |
What protocol does Anycast RP rely on? | Multicast Source Discovery Protocol (MSDP) |
What is the range for extended ACLs numbers? | 100-199, 2000-2699 |
What ending keyword is used in an ACL statement to get general information? | log |
What ending keyword is used in an ACL statement to get detailed information? | log input |
This type of ACL is compiled and put into a table for faster processing | Turbo ACL |
What is the function of uPRF? | To stop spoofed packets |
What is required to run uPRF? | CEF |
What two actions can be taken on a uPRF offending packet? | drop or log |
What interface command enables uPRF? | ip verify unicast reverse-path |
What two uPRF modes are there and what is the difference? | Strict mode says the packet has to be on the correct interface, Loose mode says that the router only has to have a route for that specific subnet |
What is a limitation of uPRF's visibility? | It can't see packets encapsulated inside tunnels |
What is IP Source Guard? | Protection against spoofing |
What is necessary for IP Source Guard to function? | DHCP Snooping |
How does CBAC work? | It watches traffic leave the network and temporarily permits return traffic |
Where can you apply the CBAC inspect rule? | In the inbound direction of the internal direction or the outbound direction of the external interface |
What two benefits do SPs get from using MPLS? | BGP free core, offer L2/L3 VPNs to customers |
What is the size of an MPLS header? | 4 bytes |
Describe the makeup of the MPLS header. | 20 bit Label, 3 bit EXP, 1 bit BoS, 8 bit TTL |
What are MPLS labels bound to? | Forwarding Equivalency Class (FEC) |
What table does the MPLS router use to switch traffic? | LFIB |
What MPLS router imposes labels? | PE or LER |
What MPLS router switches traffic based only on MPLS label? | P or LSR |
What three major operations to MPLS PE and P routers perform? | push, swap, and pop |
What is Penultimate Hop Popping (PHP)? | The next to last SP router performs to pop operation |
How does the PE signal that it wants its peer to perform PHP? | Advertising an implicit-null label (reserved label 3) |
What are the two MPLS label protocols? | LDP and TDP |
How does MPLS LDP and TDP establish adjacencies? | Relies on the IGP |
How does MPLS protocols LDP and TDP advertise IGP routes by default? | Automatically |
What MPLS protocol is typically used with Traffic Engineering and requires manually configured tunnels? | RSVP |
What protocol, address, and port does TDP use to discover MPLS neighbors? | UDP broadcast to port 711 |
What protocol, address, and port does LDP use to discover MPLS neighbors? | UDP multicast to 224.0.0.2, port 646 |
What TCP ports do TDP and LDP use? | TDP - 711, LDP - 646 |
What are the 3 steps for enabling MPLS protocol TDP? | enable CEF, set protocol, enable MPLS on the interface |
What command can be used to discover the remote MPLS label protocol? | debug ip packet detail |
Where is the TCP session sourced from in MPLS TDP and LDP? | router-ID interface |
Command to modify MPLS LDP router-id? | mpls ldp discovery transport-address |
How does an MPLS header get It's TTL value? | Copied from the IP packet |
Command for VRF aware static routes? | ip route vrf ō |
What is added to a VPNv4 route in MP-BGP to make it globally unique? What is its length? | Route Distinguisher (RD), 8 bytes |
What BGP community is used to control the importing and exporting of routes? What is its length? | route-target, 8 bytes |
What mechanisms allows VPNv4 route control on a per prefix basis? | import map and export map |
What is the format for a route distinguisher or a route-target? | ASN:nn or IPv4address:nn |
How does a VPNv4 speaker know to accept VPNv4 routes? | The route-target has to match a local VRF |
How does a MPLS PE exchange IPv4 routes with a CE? | VRF aware protocols |
What is needed when BGP is not the PE-CE protocol? | redistribution |
What are the 8 fixed fields of an IPv6 header? | Version, Traffic Class, Flow Label, Payload Length, Next Header, Hop Limit, Source Address, Destination Address |
What two shortcuts are there in IPv6 Address? | Replace fields of successive zeroes with a '::' once, Trim leading zeroes in every field |
What three address types exist in IPv6? | Unicast, Multicast, Anycast |
What are the 4 main address space types in IPv6? | global unicast, site local, link local, multicast |
What is the range of the first field of Global Unicast addresses in IPv6? | 2000 - 3FFF |
What value does the first field in the IPv6 site local address have? | FEC0 |
What value does the first field in the IPv6 link local address have? | FE80 |
What value does the first field in the IPv6 multicast address start with? | FF |
How are modified EUI IPv6 address portion derived? | 48 bit MAC address with 7th most significant bit flipped, 'FFFE' inserted in the middle |
How is the L2 next hop resolved in IPv6 NMBA networks? | Statically |
This IPv6 ND message asks for information about a neighbor | Neighbor Solicitation (NS) |
This IPv6 ND message is used for self-advertisement to other neighbors | Neighbor Advertisement (NA) |
This IPv6 ND message asks for information about local routers | Router Solicitation (RS) |
This IPv6 ND message self-advertises as an active router | Router Advertisement (RA) |
This IPv6 mechanism sends a neighbor solicitation to the solicited node multicast for unique address check | Duplicate Address Detection (DAD) |
What IPv6 address is used to self-advertise to everyone on the link? | FF02::1 |
Command to resolve a corresponding L2 address to an IPv6 address on a multipoint interface? | ipv6 neighbor (ipv6 address) (interface) (mac address) |
Command in IPv6 that mimics IPv4 command 'show arp' | show ipv6 neighbors |
What is the IPv6 replacement for IGMP? | Multicast Listener Discovery (MLD) |
What new feature does MLD have that IGMP version 3 did not? | explicit tracking of receivers |
What is the Embedded Rendezvous Point mechanism in IPv6? | The RP address is embedded into the multicast group address |
What types of tunnels are available in IPv6 multicast? | IPv6 multicast over IPv4 tunnels, IPv6 multicast over IPv6 tunnels |
What are three common IPv6 multicast address scopes? | 01 - node local, 02 - link local, 05 - site local |
What are the two groups of IPv6 over IPv4 tunnels? | static and automatic |
Which IPv6 tunnel is the allows for multiple protocols to travel over the same tunnel? (static or automatic) | GRE, static |
Which IPv6 tunnel is good for point-to-point connections, has less overheard, but can't transport CLNS? (static or automatic) | IPv6IP, static |
Which IPv6 tunnel automatically determines the tunnel endpoint? (static or automatic) | 6to4, automatic |
Which IPv6 tunnel mode provides automatic host to route and host to host tunneling? (static or automatic) | ISATAP, automatic |
Command to turn on IPv6 routing? | ipv6 unicast-routing |
What are the 5 IPv6 routing protocols? | RIPng, EIGRPv6, OSPFv3, IS-IS, mBGP |
Which IPv6 protocols use a separate process from their IPv4 counterparts? | RIPng, EIGRPv6, OSPFv3 |
How is the initial configuration of EIGRPv6 and OSPFv3 different from IPv4? | networks are enabled by interface commands, not under the routing process |
What is different about EIGRP passive interfaces from IPv4 to IPv6? | No interface level command needed |
What is a new feature of the EIGRPv6 routing process? | It features a 'shutdown' option |
What new functionality is added to IPv6 distribute lists command? | prefix-lists |