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Test your basic knowledge |
CCNP
Start Test
Study First
Subjects
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cisco
,
it-skills
,
ccnp
Instructions:
Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can
study here
.
Match each statement with the correct term.
Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.
This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.
1. What is the command to configure a BGP RR?
This will advertise the entire classful network:<br />R1(config-router)# network 10.1.1.0<br /><br />This will advertise the the classless network:<br />R1(config-router)# network 10.1.1.0 mask 255.255.255.0<br /><br /> BGP
Router(config-router)# neighbor 192.168.1.1 remote-as 65000<br />Router(config-router)# neighbor 192.168.1.1 route-reflector-client<br /> BGP
Unicast uses a routing table looking and forwards towards the destination address.<br />Multicast forwards out multiple interfaces and away from the source and towards multiple destinations using a distribution tree.<br /> Multicast
Members leave through attrition; no leave group message. This keep traffic flowing for a period of time even with no group members. Multicast
2. What effect will placing a route to null0 have on BGP?
Router(config-router)# neighbor 192.168.1.1 remote-as 65000<br />Router(config-router)# neighbor 192.168.1.1 route-reflector-client<br /> BGP
One-to-many: video distribution<br />Many-to-many: Collaboration<br />Many-to-one: auction - polling or data collection<br />Few-to-many: auction - polling or data collection<br /> Multicast
AS-Path<br />Next Hop<br />Origin BGP
BPG will find an exact match. BGP
3. Describe 4 multicast application models and give an example of each?
R1(config-router)# neighbor 192.168.1.1 next-hop-self<br /><br />Cause each routers outgoing interface that the route traverse wihtin the AS (iBPG peers) to annouce itself as the 'next hop' instead of the next hop into the neighboring AS.<br /><br />
One-to-many: video distribution<br />Many-to-many: Collaboration<br />Many-to-one: auction - polling or data collection<br />Few-to-many: auction - polling or data collection<br /> Multicast
Idle - Router looking in routing table to see if route exists to neighbor. <br /><br />[Active - When no response to Open message] <br /><br />Connect - Router found route to neighbor and has performed the TCP three-way handshake<br /><br />Open Sent
Update from client peer - sends update to all non-client peers and client peers except for originating peer.<br />Update from non-client peer - send update to all clients in the cluster.<br />Update from EBGP peer - update sent to all client peers an
4. What is one method involving minimal configuration to prevent and multi-homed BGP network from becoming a transit AS?
Using a Distribute List to filter outbound routing updates. BGP
Class D address space<br />First bits are ALWAYS 1110<br />224.0.0.0 - 239.255.255.255<br /> Multicast
Places it in the routing table. BGP
Path Vector - policy based routing protocol.<br />Uses BGP attributes are the 'metric'. <br />Path it decides it based on 'hops' where hop is Autonomous Systems.<br /> BGP
5. IOS command to configure a rendezvous point .
Unicast uses a routing table looking and forwards towards the destination address.<br />Multicast forwards out multiple interfaces and away from the source and towards multiple destinations using a distribution tree.<br /> Multicast
Router#(config) ip pim send-rp-announce interface_type scope ttl group-list access-list Multicast
1. Weight - Administrative preference (Highest)<br /><br />2. Local Preference - Communicated between peers within AS (Highest)<br /><br />3. Self-originated - Prefer path originated locally (True)<br /><br />4. AS Path - Minimize AS hops (Shortest)<
<img src='9618cf01b9422f541fc213b74a3bd9de.png' /> Multicast
6. What are the 3 BGP tables and What is in them?
Places it in the routing table. BGP
Concatenation of the first (high order) 25 bits of the reserved MAC address range with the last (low order)23 bits of the multicast group IP address. 5 bits of overlap allowing for 32 address (2^5) for each multicast MAC address. 25 bits + 23 bits<br
Session description & announcement.<br />Transport session announcement via 224.2.127.254.<br />Creation of new sessions.<br /> Multicast
BGP Table - BGP topology database - information <br />BGP Neighbor Table - list of connected neighbors<br />IP Routing Table - Duh.<br /> BGP
7. What advantage is there it establishing a neighbor relationship using a loopback interface?
Bidirection PIM mode - designed for many to many applications.<br />Source Specific Multicast (SSM) ; builds only source specific shortest path trees.<br /> Multicast
The BGP Table<br /><br />Command = show ip bgp BGP
Loopback more resilient than physical interfaces. BGP
BPG will find an exact match. BGP
8. What is the multicast IP address space?
When not all routers within a transit AS have consistent routing information - due to not running BGP or misconfiguration or BPG speakers. Routing information is advertised but since not all routers within AS can reach the destination traffic is halt
One-to-many: video distribution<br />Many-to-many: Collaboration<br />Many-to-one: auction - polling or data collection<br />Few-to-many: auction - polling or data collection<br /> Multicast
Class D address space<br />First bits are ALWAYS 1110<br />224.0.0.0 - 239.255.255.255<br /> Multicast
This router originated the route. BGP
9. What is BGP multihoming and why would you want to do it?
When AS has more than one connection to the Internet it is called multihoming.<br />Inbound reliability<br />Better performance by selecting more optimal paths<br />Multihoming can be to one ISP or to several.<br /> BGP
Links = n(n-1)/2 BGP
RFC - 3376<br />Ability to filter multicast source (can be picky)<br />IGMPv3 membership report goes to 224.0.0.22 and may include the multicast hosts it will accept or deny.<br /> Multicast
'Periodic Flood and Prune.'<br />Initially floods multicast traffic (received on its RPF) to all its PIM neighbors. Traffic that arrives back at the router via a non-RPF is discarded.<br />Prune messages are sent on all non-RPF interfaces and RPF int
10. What is a BGP route reflector - What is it purpose?
WM<br /><br />List of AS numbers pre-pended with a list of AS numbers that the route has traversed and the originating AS at the end. 'Path to 192.168.1.0 is (65500 - 65420 - 65874)'<br /><br />This insures a loop-free environment. If BGP receives a
Must insure loopback is reachable in the routing table. BGP
Group of BGP routers being configured that have the same update policy.<br />Similar to a 'template'; members then assigned to the peer group.<br /> BGP
Since IBGP learned routes are never propagate to other IBGP peer - full mesh of IBPG peers is required within an AS. THIS IS NOT SCALABLE. <br />RR allow the propagation of routes learned by IBGP to other IBGP peers without having a full mesh of IBGP
11. Name the Well-known discretionary attributes.
Local preference<br />Atomic Aggregate BGP
Dense mode interfaces are always added to the table. <br /><br />Sparse mode interfaces are added to the table only when periodic join messages are received from downstream routers - or when a directly connected member is on the interface<br /> Multi
Update from client peer - sends update to all non-client peers and client peers except for originating peer.<br />Update from non-client peer - send update to all clients in the cluster.<br />Update from EBGP peer - update sent to all client peers an
EBGP is an adjacency between BGP peers in different AS; iBGP peers are in same AS. BGP
12. What is the IOS command to check for IGMP group members? What info does it reveal?
Routes learned through IBPG are never propogated to other IBGP speakers.<br /><br />This is a loop prevention mechanism. BGP
Router#show ip igmp group<br />Group address - interface - uptime - expires - and last reporter.<br /> Multicast
Router#(config) ip pim send-rp-announce interface_type scope ttl group-list access-list Multicast
Globally:<br />Router(config)# ip multicast-routing<br />Per Interface:<br />Router(config-if)# ip pim dense-mode<br />Enabling PIM on an interface also enables IGMP operation on that interface.<br /> Multicast
13. What are some disadvantages of multicast?
Contains information on ONE path only<br /><br />Withdrawn routes - List of IP prefixes for routes being withdrawn.<br />Path attributes - AS-Path - etc.<br />Network layer reachability information - List of IP prefixes reachable by this path. BGP
Most applications rely on UDP<br />Security issues<br />Out of order delivery & duplicate packets are a possibility during topology changes.<br />Lack of windowing/congestion control.<br /> Multicast
Update from client peer - sends update to all non-client peers and client peers except for originating peer.<br />Update from non-client peer - send update to all clients in the cluster.<br />Update from EBGP peer - update sent to all client peers an
When AS has more than one connection to the Internet it is called multihoming.<br />Inbound reliability<br />Better performance by selecting more optimal paths<br />Multihoming can be to one ISP or to several.<br /> BGP
14. What is the terminology for BGP route reflector?
15. What config would be used to configured an outbound BGP distribute list to block all routes from being advertised except ones from 192.168.0.0 /24 network to neighbors 10.1.1.1 and 10.1.1.2?
R2(config)# access-list 1 permit 192.168.0.0 0.0.0.255<br />R1(config-router)# neighbor 10.1.1.1 distribute-list 1 out<br />R1(config-router)# neighbor 10.1.1.2 distribute-list 1 out<br /> BGP
O<br />Cisco only.<br />Routes with higher weight are preferred (0 - 65535) . Paths that the router originates have 32768; other paths have default of 0.<br /> BGP
Since IBGP learned routes are never propagate to other IBGP peer - full mesh of IBPG peers is required within an AS. THIS IS NOT SCALABLE. <br />RR allow the propagation of routes learned by IBGP to other IBGP peers without having a full mesh of IBGP
Router(config-router)# neighbor 192.168.1.1 remote-as 65000<br />Router(config-router)# neighbor 192.168.1.1 route-reflector-client<br /> BGP
16. What are the basic commands to enable BGP - define a BGP peer relationship and advertise a network?
When using the <span style='font-style:italic;'>classful</span> method - at least one subnet of the classful range must reside in the IP routing table.<br /><br />When using the <span style='font-style:italic;'>classless</span> method the exact subne
224.0.0.1 - All systems<br />224.0.0.2 - All routers<br />224.0.0.4 - DVMRP routers<br />224.0.0.5 - All OSPF<br />224.0.0.6 - All OSPF DR<br />224.0.0.9 - RIP v2 routers<br />224.0.0.10 - EIGRP routers<br />224.0.0.13 - PIM routers<br />224.0.0.15 -
Router#(config) router bgp 1<br />Router#(config-router) neighbor 192.168.1.1 remote-as 1<br />Router#(config-router) network 192.168.0. mask 255.255.255.0<br /> BGP
Contains information on ONE path only<br /><br />Withdrawn routes - List of IP prefixes for routes being withdrawn.<br />Path attributes - AS-Path - etc.<br />Network layer reachability information - List of IP prefixes reachable by this path. BGP
17. Describe how PIM-Sparse-Dense operates.
18. What is a BGP peer group?
19. Explain the way RR handles route updates.
Most applications rely on UDP<br />Security issues<br />Out of order delivery & duplicate packets are a possibility during topology changes.<br />Lack of windowing/congestion control.<br /> Multicast
Update from client peer - sends update to all non-client peers and client peers except for originating peer.<br />Update from non-client peer - send update to all clients in the cluster.<br />Update from EBGP peer - update sent to all client peers an
RFC 2362<br />Pull model - traffic only forwarded to the parts of the network that need it. Sender registers with the RP which is a proxy to group members.<br />Last hop routers to receiver knows the group RP IP address and sends a (* -G) join toward
IGMP Snooping - requires special ASICS can degrade performance with it; is supported by multiple vendors.<br />CGMP - Cisco proprietary - only work on Cisco hardware; resource friendly<br />GMRP - Replaced by MRP; obscure<br />Manually - Performance
20. What does BGP use for communication? What advantage does it offer?
TCP port 179<br />Reliability; uses sliding window<br />Triggered - incremental updates made very efficient<br /> BGP
RFC - 3376<br />Ability to filter multicast source (can be picky)<br />IGMPv3 membership report goes to 224.0.0.22 and may include the multicast hosts it will accept or deny.<br /> Multicast
Unicast uses a routing table looking and forwards towards the destination address.<br />Multicast forwards out multiple interfaces and away from the source and towards multiple destinations using a distribution tree.<br /> Multicast
BGP specifies that it can advertise to its peers in neighboring AS's only routes that it uses.<br />BGP cannot influence how a neighboring AS will route your traffic BUT it can influence how your traffic gets to the neighboring AS. <br /> BGP
21. Name the Well-known mandatory attributes.
AS-Path<br />Next Hop<br />Origin BGP
Well-known Mandatory - Must be supported and propagated.<br />Well-known Discretionary - Must be supported; propagation optional.<br />Optional Transitive - Marked as partial if unsupported by neighbor.<br />Option Nontransitive - Deleted is unsuppor
ON<br />Displayed as metric in Cisco IOS; lower is preferred. Default is 0. Indicated to external AS the preferred path into the AS.<br />'Influence inbound traffic to an AS'<br />By default ONLY compares if neighbors AS is same for all routes being
Idle - Router looking in routing table to see if route exists to neighbor. <br /><br />[Active - When no response to Open message] <br /><br />Connect - Router found route to neighbor and has performed the TCP three-way handshake<br /><br />Open Sent
22. What is the layer 2 multicast address and how is it formed? What potential problem is there with this?
SPT (S -G) consume more memory because there is an entry for each source BUT traffic is sent over optimal path to receiver.<br />Shared distribution tree state entries (* -G) consume less CPU but may take suboptimal path to receiver.<br /> Multicast
Concatenation of the first (high order) 25 bits of the reserved MAC address range with the last (low order)23 bits of the multicast group IP address. 5 bits of overlap allowing for 32 address (2^5) for each multicast MAC address. 25 bits + 23 bits<br
BPG will find an exact match. BGP
Contains information on ONE path only<br /><br />Withdrawn routes - List of IP prefixes for routes being withdrawn.<br />Path attributes - AS-Path - etc.<br />Network layer reachability information - List of IP prefixes reachable by this path. BGP
23. What is the key difference between how a multicast routing protocol forwards packets versus a unicast routing protocol?
It actually determines which networks are advertised. BGP
<img src='9618cf01b9422f541fc213b74a3bd9de.png' /> Multicast
Unicast uses a routing table looking and forwards towards the destination address.<br />Multicast forwards out multiple interfaces and away from the source and towards multiple destinations using a distribution tree.<br /> Multicast
Router#(config) ip pim send-rp-announce interface_type scope ttl group-list access-list Multicast
24. What does PIM use for its multicast routing calculations?
Using a Distribute List to filter outbound routing updates. BGP
'Periodic Flood and Prune.'<br />Initially floods multicast traffic (received on its RPF) to all its PIM neighbors. Traffic that arrives back at the router via a non-RPF is discarded.<br />Prune messages are sent on all non-RPF interfaces and RPF int
The unicast routing table.<br />No routing updates are sent between PIM routers.<br /> Multicast
One-to-many: video distribution<br />Many-to-many: Collaboration<br />Many-to-one: auction - polling or data collection<br />Few-to-many: auction - polling or data collection<br /> Multicast
25. What is a BGP black hole and how is it avoided?
* = Best route<br />> = Route has been inserted into the routing table<br /> BGP
When not all routers within a transit AS have consistent routing information - due to not running BGP or misconfiguration or BPG speakers. Routing information is advertised but since not all routers within AS can reach the destination traffic is halt
Globally:<br />Router(config)# ip multicast-routing<br />Per Interface:<br />Router(config-if)# ip pim dense-mode<br />Enabling PIM on an interface also enables IGMP operation on that interface.<br /> Multicast
Cluster - combination of RR and its clients. Can have multiple clusters in an AS. <br />Originator ID - carries router ID of the route's originator<br />Cluster ID - configured when multiple RR in a cluster.<br />Cluster list - sequence of cluster ID
26. Explain the Weight attribute.
* = Best route<br />> = Route has been inserted into the routing table<br /> BGP
Router#show ip igmp interface fa0/0<br /> Multicast
Open - Version - AS - Hold Time - BGP Router ID - Optional Parameters<br />Keepalive - Sent every 60 seconds by default; hold time 180 Seconds.<br />Update - Information on only ONE path; <br />Notification - When error condition detected<br /> BGP
O<br />Cisco only.<br />Routes with higher weight are preferred (0 - 65535) . Paths that the router originates have 32768; other paths have default of 0.<br /> BGP
27. What command will produce the following output and What is it displaying?<br /><br /><img src='5d3c9233dd205ee4319ef0ac2fc07460.jpg' />
Since IBGP learned routes are never propagate to other IBGP peer - full mesh of IBPG peers is required within an AS. THIS IS NOT SCALABLE. <br />RR allow the propagation of routes learned by IBGP to other IBGP peers without having a full mesh of IBGP
Routes learned through IBPG are never propogated to other IBGP speakers.<br /><br />This is a loop prevention mechanism. BGP
The Source and Share Tree models are the working model of how the tree is built; all multicast routing protocols fit into one or both. This is the 'theory' or model.<br />PIM-DM's operational falls in the source tree model and PIM-SM is classified an
The BGP Table<br /><br />Command = show ip bgp BGP
28. Explain the relationship between MBone - DVMRP - PIM - IGMP - CGMP hosts - routers and switches?
29. What are three different common ways to perform BGP multihoming with regard to routing table?
ISP passes only default route to AS.<br />ISP passes default route and provider owned select routes to AS.<br />ISP passes all routes to AS.<br /> BGP
ON<br />Displayed as metric in Cisco IOS; lower is preferred. Default is 0. Indicated to external AS the preferred path into the AS.<br />'Influence inbound traffic to an AS'<br />By default ONLY compares if neighbors AS is same for all routes being
EBGP = 20<br />iBGP = 200<br /> BGP
This will advertise the entire classful network:<br />R1(config-router)# network 10.1.1.0<br /><br />This will advertise the the classless network:<br />R1(config-router)# network 10.1.1.0 mask 255.255.255.0<br /><br /> BGP
30. What are the 4 BGP packet types? What do they contain?
When AS has more than one connection to the Internet it is called multihoming.<br />Inbound reliability<br />Better performance by selecting more optimal paths<br />Multihoming can be to one ISP or to several.<br /> BGP
RFC 2236<br />Leave and join latency resolved<br />Group specific query to G instead of 224.0.0.1<br />Leave group message<br />Election of querier (lowest IP) on broadcast medium with multiple routers <br /> Multicast
Update from client peer - sends update to all non-client peers and client peers except for originating peer.<br />Update from non-client peer - send update to all clients in the cluster.<br />Update from EBGP peer - update sent to all client peers an
Open - Version - AS - Hold Time - BGP Router ID - Optional Parameters<br />Keepalive - Sent every 60 seconds by default; hold time 180 Seconds.<br />Update - Information on only ONE path; <br />Notification - When error condition detected<br /> BGP
31. What does IGMPv2 add?
RFC 2236<br />Leave and join latency resolved<br />Group specific query to G instead of 224.0.0.1<br />Leave group message<br />Election of querier (lowest IP) on broadcast medium with multiple routers <br /> Multicast
R1# clear ip bgp <br />R1# clear ip bgp soft in<br />R1# clear ip bgp * soft out<br />R1# clear ip bgp 10.1.1.1 soft in<br /><br /> BGP
The neighbor expects to see the updates from the source address configured in the neighbor statement. BGP
Links = n(n-1)/2 BGP
32. Explain the AS format and ranges?
R1(config-router)#neighbor 192.168.1.1 password MyPassword<br /><br />OR<br /><br />R1(config-router)#neighbor MyPeerGroup password MyPassword<br /> BGP
16 bit number 1 to 65535<br />1-64511: Public AS<br />64512-6535: Reserved for private AS<br /> BGP
(S -G) - 'S comma G'; Source sending to the group. Typically reflect a source tree but can appear on a shared tree. Traffic forwarded via the shortest path from the source.<br />(* -G) - 'Star comma G'; Any source sending to the group. Traffic forwar
The BGP Table<br /><br />Command = show ip bgp BGP
33. What is the hop-by-hop routing paradigm of BGP?
34. What are the 4 categories of BGP attributes and what do they mean?
Bidirection PIM mode - designed for many to many applications.<br />Source Specific Multicast (SSM) ; builds only source specific shortest path trees.<br /> Multicast
Unicast uses a routing table looking and forwards towards the destination address.<br />Multicast forwards out multiple interfaces and away from the source and towards multiple destinations using a distribution tree.<br /> Multicast
IGMP Snooping - requires special ASICS can degrade performance with it; is supported by multiple vendors.<br />CGMP - Cisco proprietary - only work on Cisco hardware; resource friendly<br />GMRP - Replaced by MRP; obscure<br />Manually - Performance
Well-known Mandatory - Must be supported and propagated.<br />Well-known Discretionary - Must be supported; propagation optional.<br />Optional Transitive - Marked as partial if unsupported by neighbor.<br />Option Nontransitive - Deleted is unsuppor
35. What are some of the obstacles with IGMP and multicast in general as it relates to layer 2/switches?
IGMP is a layer 3 protocol<br />Switches treat multicast just like broadcast (forward out all ports except the one one which is was received)<br />By definition a pure layer 2 devices do not have a mechanism to see IGMP packets or facilitate the rela
* = Best route<br />> = Route has been inserted into the routing table<br /> BGP
Places it in the routing table. BGP
224.0.0.1 - All systems<br />224.0.0.2 - All routers<br />224.0.0.4 - DVMRP routers<br />224.0.0.5 - All OSPF<br />224.0.0.6 - All OSPF DR<br />224.0.0.9 - RIP v2 routers<br />224.0.0.10 - EIGRP routers<br />224.0.0.13 - PIM routers<br />224.0.0.15 -
36. Explain the Next-Hop attribute. How does this differ from IGP's? In what environment might this be problematic?
Cluster - combination of RR and its clients. Can have multiple clusters in an AS. <br />Originator ID - carries router ID of the route's originator<br />Cluster ID - configured when multiple RR in a cluster.<br />Cluster list - sequence of cluster ID
Must insure loopback is reachable in the routing table. BGP
Local preference<br />Atomic Aggregate BGP
WM<br />Next hop address is entry point into the next AS along the path to that destination network. It does a recursive lookup to the routing table which should have learned the route from its IGP.<br />in IBGP the next hop advertised by EBGP should
37. What does a '*' and '>' mean in the BGP table?
Must insure loopback is reachable in the routing table. BGP
* = Best route<br />> = Route has been inserted into the routing table<br /> BGP
1. Weight - Administrative preference (Highest)<br /><br />2. Local Preference - Communicated between peers within AS (Highest)<br /><br />3. Self-originated - Prefer path originated locally (True)<br /><br />4. AS Path - Minimize AS hops (Shortest)<
Path Vector - policy based routing protocol.<br />Uses BGP attributes are the 'metric'. <br />Path it decides it based on 'hops' where hop is Autonomous Systems.<br /> BGP
38. What are two methods of establishing a gateway of last resort?
Default-Network<br />Static route<br /> BGP
IANA delegates to Regional Internet Registries (RIRs):<br />ARIN - AfriNIC - APNIC - LACNIC and RIPE NCC<br /> BGP
BGP specifies that it can advertise to its peers in neighboring AS's only routes that it uses.<br />BGP cannot influence how a neighboring AS will route your traffic BUT it can influence how your traffic gets to the neighboring AS. <br /> BGP
Language between local router interface and hosts.<br />IGMP - ICMP - similarities <br />TTL is usually 1; RFC states it should never leave local subnet.<br />Creates and maintains group membership for hosts wishing to participate in a multicast grou
39. Explain the Origin attribute.
40. State 3 functions SDR performs?
Session description & announcement.<br />Transport session announcement via 224.2.127.254.<br />Creation of new sessions.<br /> Multicast
ON<br />Displayed as metric in Cisco IOS; lower is preferred. Default is 0. Indicated to external AS the preferred path into the AS.<br />'Influence inbound traffic to an AS'<br />By default ONLY compares if neighbors AS is same for all routes being
One-to-many: video distribution<br />Many-to-many: Collaboration<br />Many-to-one: auction - polling or data collection<br />Few-to-many: auction - polling or data collection<br /> Multicast
RFC 1112<br />Sends membership query every 60 - 120 seconds to 224.0.0.1<br />Hosts send membership report in response to the query<br /> Multicast
41. What is one mechanism that GURANTEES the BGP AS path is loop free?
The router will not accept a routing update that includes its AS number in the path. BGP
Concatenation of the first (high order) 25 bits of the reserved MAC address range with the last (low order)23 bits of the multicast group IP address. 5 bits of overlap allowing for 32 address (2^5) for each multicast MAC address. 25 bits + 23 bits<br
0100.5e00.0000 - 0100.5e7f.ffff - IANA reserved. Multicast
When not all routers within a transit AS have consistent routing information - due to not running BGP or misconfiguration or BPG speakers. Routing information is advertised but since not all routers within AS can reach the destination traffic is halt
42. Explain the methods of advertising networks in BGP.
<img src='9618cf01b9422f541fc213b74a3bd9de.png' /> Multicast
This will advertise the entire classful network:<br />R1(config-router)# network 10.1.1.0<br /><br />This will advertise the the classless network:<br />R1(config-router)# network 10.1.1.0 mask 255.255.255.0<br /><br /> BGP
O<br />Cisco only.<br />Routes with higher weight are preferred (0 - 65535) . Paths that the router originates have 32768; other paths have default of 0.<br /> BGP
Links = n(n-1)/2 BGP
43. What are the two multicast distribution tree types models and differences?
44. What command is used to override the Next-Hop attribute of BGP? What does this do and when would you use this?
45. Explain the concept of RPF.
EBGP is an adjacency between BGP peers in different AS; iBGP peers are in same AS. BGP
Group of BGP routers being configured that have the same update policy.<br />Similar to a 'template'; members then assigned to the peer group.<br /> BGP
Router(config-router)# neighbor 192.168.1.1 remote-as 65000<br />Router(config-router)# neighbor 192.168.1.1 route-reflector-client<br /> BGP
Reverse Path Forwarding is the forwarding logic multicast of multicast. <br />It is the opposite of unicast in that is forwards AWAY from source as opposed to towards the receiver.<br /> Multicast
46. What is the command to configure a BGP RR?<br />
Router(config-router)# neighbor 192.168.1.1 remote-as 65000<br />Router(config-router)# neighbor 192.168.1.1 route-reflector-client<br /> BGP
IANA delegates to Regional Internet Registries (RIRs):<br />ARIN - AfriNIC - APNIC - LACNIC and RIPE NCC<br /> BGP
Rule: Router must be known by an IGP before it may be advertised by BGP peers.<br />Prevents 'blackholes' when AS is a transit network and not all speaker are running BGP<br />Should be left on it AS is a transit AS and not all routers run BGP.<br />
ON<br />Displayed as metric in Cisco IOS; lower is preferred. Default is 0. Indicated to external AS the preferred path into the AS.<br />'Influence inbound traffic to an AS'<br />By default ONLY compares if neighbors AS is same for all routes being
47. What is the full mesh versus partial mesh IBGP and What are the implications of each?
Partial mesh iBPG is where not all BGP speaks within and AS have an established neighbor relationship. <br />Full mesh is every BGP speaker has a neighbor (peer) with each other. <br />Routing updates are not replcated in iBPG the peers do not pass i
R2(config)# access-list 1 permit 192.168.0.0 0.0.0.255<br />R1(config-router)# neighbor 10.1.1.1 distribute-list 1 out<br />R1(config-router)# neighbor 10.1.1.2 distribute-list 1 out<br /> BGP
MOSPF<br />DVMRP<br />CBT<br />PIM Dense Mode<br />PIM Sparse Mode<br />PIM Sparse-Dense Mode<br /> Multicast
R1(config-router)# neighbor 192.168.1.1 next-hop-self<br /><br />Cause each routers outgoing interface that the route traverse wihtin the AS (iBPG peers) to annouce itself as the 'next hop' instead of the next hop into the neighboring AS.<br /><br />
48. What are 2 stipulations of advertising networks BGP?
49. Explain the multicast routing table distribution tree notations.
50. What is the formula to determine number of links in a full mesh topology?
Sends a leave message to 224.0.0.2<br />Router then sends a group specific query<br />Remaining member(s) send a report so group remains active.<br /> Multicast
Works if router has multiple parallel paths to a destination.<br />ONLY affect number of routes in IP routing table not the route selected at best in the BGP table.<br />Will load balance across equal cost paths in EGP session.<br /> BGP
This will advertise the entire classful network:<br />R1(config-router)# network 10.1.1.0<br /><br />This will advertise the the classless network:<br />R1(config-router)# network 10.1.1.0 mask 255.255.255.0<br /><br /> BGP
Links = n(n-1)/2 BGP