160 Questions
What is the autonomous system number configured on the PUNE-PE router?
9829
What is the IP address of the neighbor configured with the remote-as 10?
172.16.16.70
What is the purpose of the 'next-hop-self' command?
To set the next hop to the local router's IP address
What is the address family configured for VPN?
vpnv4
What is the command to disable BGP synchronization?
no synchronization
What is the command to shut down an interface on the CHENNAI-PE router?
shut
What is the update-source configured for the neighbor 192.168.5.254?
loopback 0
What is the command to save the configuration on the PUNE-PE router?
wr
What is the purpose of the 'no shutdown' command?
To bring up an interface
What is the IP address configured on the loopback interface?
20.50.0.1
What is the command to verify the routing table for a specific VRF?
show ip route vrf ibm
What is the command to verify the BGP neighbors for a specific VRF?
show ip bgp vpnv4 vrf ibm neighbors
What is the command to ping a destination IP address in a specific VRF?
ping vrf ibm 10.20.0.1
What is the command to configure a BGP process?
router bgp
What is the command to verify the MPLS forwarding table for a specific VRF?
show mpls forwarding vrf ibm
What is the purpose of the 'network' command in BGP?
To advertise a network in BGP
What is the purpose of the 'no shutdown' command in the configuration?
To enable the interface
What is the AS number of the neighboring router in the BGP configuration?
9829
What is the purpose of the 'no synchronization' command in the BGP configuration?
To disable synchronization of BGP and IGP
What is the purpose of the command 'no router ospf 10 vrf ibm' on the PUNE-PE router?
To disable OSPF process on the router
What is the purpose of the 'controller' command in the configuration?
To configure the channel group
What is the IP address configured as the static route destination on the PUNE-PE router for VRF IBM?
172.16.16.70
What is the IP address of the loopback interface on SUN-CE-1?
20.40.0.1
What is the VRF name configured on the PUNE-PE router for the network 20.40.0.0/24?
SUN
What is the purpose of the command 'exit-address-family' on the PUNE-PE router?
To exit the BGP address family configuration mode
What is the purpose of the 'write memory' command?
To save the configuration to the startup configuration
What is the purpose of the 'no mpls ip' command?
To disable MPLS on the interface
What is the network configured on the PUNE-PE router for VRF SUN using the 'network' command?
20.40.0.0/24
What is the AS number of the BGP instance on SUN-CE-2?
50
Why is the 'no redistribute ospf 10 match internal external 1 external 2' command used on the PUNE-PE router?
To disable OSPF redistribution on the router
What is the purpose of the command 'ip route vrf ibm 10.10.0.0 255.255.0.0 172.16.16.70' on the PUNE-PE router?
To configure static route on the router
What is the router prompt displayed after exiting the configuration mode on the PUNE-PE router?
PUNE-PE#
What is the purpose of the 'no synchronization' command in BGP configuration?
To disable synchronization of iBGP and IGP
What is the purpose of the 'no auto-summary' command in BGP configuration?
To disable autosummary of routes
What is the purpose of the 'neighbour' command in BGP configuration?
To establish a BGP neighbour relationship
What is the purpose of the 'network' command in BGP configuration?
To advertise a network in BGP
What is the purpose of the 'no router ospf 9829' command?
To disable OSPF routing with process ID 9829
What is the purpose of the 'no ip cef distributed' command?
To disable IP CEF distributed
What is the purpose of the 'interface loopback 1' command?
To create a loopback interface
What is the purpose of the 'write memory' command?
To save the configuration changes to the startup configuration
What is the purpose of the 'auto-cost reference-bandwidth' command in OSPF configuration?
To set the reference bandwidth for automatic cost calculation
What is the effect of the 'no router bgp' command?
It removes a BGP process
What is the purpose of the 'network' command in OSPF configuration?
To specify the networks to be advertised in OSPF
What is the purpose of the 'passive-interface' command in OSPF configuration?
To disable OSPF on an interface
What is the effect of the 'clear ip ospf' command?
It resets the OSPF process
What is the purpose of the 'write memory' command?
To save the current configuration to memory
What is the purpose of the 'conf t' command?
To enter configuration mode
What is the effect of the 'no router ospf' command?
It removes an OSPF process
What is the purpose of the 'update-source loopback 0' command in the BGP configuration?
To specify the source IP address for BGP updates
What is the benefit of using MP-BGP in a network?
It allows for the exchange of VPNv4 prefixes
What is the purpose of the 'next-hop-self' command in the BGP configuration?
To set the next hop address to the local router
What is the purpose of the 'no bgp default ipv4-unicast' command?
To disable BGP default IPv4 unicast configuration
What is the benefit of using OSPF routing in a network?
It provides fast convergence and scalability
What is the purpose of the 'address-family ipv4 vrf' command?
To configure the address family for a VRF
What is the purpose of the 'no auto-summary' command in the BGP configuration?
To disable auto-summary of BGP routes
What is the purpose of the 'neighbor' command in the BGP configuration?
To define a BGP neighbor
What is the primary purpose of MP-iBGP in MPLS Layer 3 VPNs?
To handle huge traffic of routing updates from other Autonomous Systems
What is the command used to disable OSPF routing protocol on a Cisco router?
no router ospf
What is the purpose of the 'ip route 0.0.0.0 0.0.0.0' command?
To configure a default route
Why is OSPF not used to handle huge traffic of routing updates from other Autonomous Systems?
Because OSPF is an interior gateway routing protocol
What is the purpose of the 'write memory' command?
To save the configuration changes to the startup-config file
What is the Autonomous System Boundary Router (ASBR) responsible for?
Exchanging global internet routing updates with other Autonomous Systems
What is the purpose of the 'conf t' command?
To enter the configuration mode
What is the command used to configure a default route on a Cisco router?
ip route 0.0.0.0 0.0.0.0
What is the purpose of the 'auto-cost reference-bandwidth' command in OSPF configuration?
To set the reference bandwidth for cost calculation
What is the command to remove BGP configuration on SUN-CE-1?
no router bgp 40
What is the purpose of the 'network' command in OSPF configuration?
To specify the networks that OSPF will advertise
What is the command to reset OSPF process on SUN-CE-1?
clear ip ospf 2100 process
What is the autonomous system number configured on SUN-CE-2 for OSPF?
50
What is the purpose of the 'passive-interface' command in OSPF configuration?
To disable OSPF routing on an interface
What is the command to save the configuration on SUN-CE-2?
write memory
What is the purpose of the 'router ospf' command?
To configure an OSPF process
What is the purpose of the 'auto-cost reference-bandwidth 1000' command in OSPF configuration?
To set the reference bandwidth for calculating OSPF cost
What is the purpose of the 'redistribute ospf 10 match internal external 1 external 2' command in MP-BGP configuration?
To redistribute OSPF routes into BGP
What is the purpose of the 'router ospf 10 vrf ibm' command?
To configure OSPF routing on a specific VRF
What is the purpose of the 'network 172.16.16.68 0.0.0.3 area 0' command in OSPF configuration?
To specify the OSPF network and area
What is the purpose of the 'address-family ipv4 vrf ibm' command in MP-BGP configuration?
To configure BGP routing on a specific VRF
What is the purpose of the 'neighbor 172.16.16.70 remote-as 10' command in MP-BGP configuration?
To specify the BGP neighbor IP address and autonomous system number
What is the purpose of the 'exit-address-family' command in MP-BGP configuration?
To exit the address-family configuration mode
What is the purpose of the 'router bgp 9829' command?
To configure BGP routing on a specific autonomous system
What is the purpose of the command 'channel-group 0 time-slot 1-31'?
To configure the channel group on the controller
What is the purpose of the command 'no router ospf 9829'?
To disable the OSPF routing protocol
What is the purpose of the command 'passive-interface loopback 0'?
To make the loopback interface passive
What is the purpose of the command 'no mpls ip'?
To disable the MPLS on the interface
What is the purpose of the command 'shut'?
To disable the interface
What is the purpose of the command 'controller e1 4/0/0'?
To configure the controller
What is the purpose of the command 'auto-cost reference-bandwidth 1000'?
To set the reference bandwidth for OSPF cost calculation
What is the purpose of the command 'write memory'?
To save the configuration to the startup-config
What is the main advantage of MPLS Layer 3 VPNs over IPSec VPNs in complex topologies?
Reduced configuration overhead
What is the role of the Customer Edge (CE) router in an MPLS Layer 3 VPN?
To peers with the service provider's PE router using the IGP or eBGP
What is used to distribute customer prefixes within the provider's network?
MP-BGP
What is the path that traffic follows in an MPLS network?
A predetermined label-switched path (LSP)
What is the purpose of the Multiprotocol Label Switching (MPLS) virtual private network (VPN)?
To interconnect multiple sites through a provider core network
What is the benefit of using MP-BGP in a network?
Enhanced network scalability
What is the role of the Provider Edge (PE) router in an MPLS Layer 3 VPN?
To form a VPN with other PE routers
What is the configuration objective of the chapter?
To understand MPLS VPN configuration using MP-iBGP/eBGP, MP-iBGP/OSPF, and MP-iBGP/Static/Default
What is the purpose of the 'auto-cost reference-bandwidth' command in OSPF configuration?
To set the reference bandwidth for OSPF cost calculation
What is the effect of the 'clear ip ospf' command?
It resets the OSPF process
What is the purpose of the 'passive-interface' command in OSPF configuration?
To disable OSPF on an interface
What is the purpose of the 'network' command in OSPF configuration?
To specify the networks that OSPF will advertise
What is the effect of the 'no router ospf' command?
It disables OSPF routing
What is the purpose of the 'neighbor 192.168.0.254 update-source loopback 0' command in the BGP configuration?
To specify the source interface for the BGP session
What is the purpose of the 'write memory' command?
To save the configuration to the startup-configuration
What is the function of the 'no bgp default ipv4-unicast' command in the BGP configuration?
To disable IPv4 unicast routing
What is the purpose of the 'conf t' command?
To enter the configuration mode
What is the purpose of the 'address-family ipv4 vrf ibm' command in the BGP configuration?
To enter the address-family configuration mode for the VRF 'ibm'
What is the effect of the 'no router bgp' command?
It disables BGP routing
What is the effect of the 'neighbor 172.16.16.66 next-hop-self' command in the BGP configuration?
To set the next hop of the BGP route to the IP address of the local router
What is the purpose of the 'send-community both' command in the BGP configuration?
To send both standard and extended community attributes to the BGP neighbor
What is the purpose of the 'no auto-summary' command in the BGP configuration?
To disable automatic summarization of routes
What is the function of the 'address-family vpnv4' command in the BGP configuration?
To enter the address-family configuration mode for VPNv4
What is the purpose of the 'neighbor 192.168.0.254 activate' command in the BGP configuration?
To activate the BGP neighbor
What is the purpose of the command 'no router bgp 40' on SUN-CE-1?
To remove the BGP configuration on SUN-CE-1
What is the effect of the command 'clear ip ospf 2100 process' on SUN-CE-1?
Resets the OSPF process
What is the purpose of the command 'auto-cost reference-bandwidth 1000' on SUN-CE-1?
To configure the OSPF cost
What is the purpose of the command 'passive-interface loopback 1' on SUN-CE-1?
To configure the loopback interface as passive
What is the purpose of the command 'write memory' on SUN-CE-1?
To save the configuration
What is the purpose of the command 'router ospf 50' on SUN-CE-2?
To configure OSPF on SUN-CE-2
What is the purpose of the command 'network 20.50.0.0 0.0.255.255 area 0' on SUN-CE-2?
To configure the OSPF network
What is the purpose of the command 'clear ip ospf 50 process' on SUN-CE-2?
To reset the OSPF process
What is the primary reason MP-iBGP is used instead of OSPF in Autonomous System Boundary routers?
To handle huge traffic of routing updates
What is the command used to remove OSPF configuration on SUN-CE-1 router?
no router ospf 40
What is the purpose of the 'write memory' command?
To save changes to the running configuration
What is the interface used for default routing on IBM-CE-3 router?
Serial 4/0/0:0
What is the Autonomous System Boundary router's role?
To exchange global internet routing updates with other Autonomous Systems
What is the command used to configure a default route on SUN-CE-2 router?
ip route 0.0.0.0 0.0.0.0 pos 3/1
Why is MP-iBGP used in configuration of MPLS Layer 3 VPNs?
To handle huge traffic of routing updates
What is the purpose of removing OSPF configuration on the routers?
To configure default routing
What is the purpose of the 'auto-cost reference-bandwidth' command in OSPF configuration?
To set the reference bandwidth for OSPF cost calculations
What is the effect of the 'clear ip ospf' command?
It resets the OSPF process
What is the purpose of the 'network' command in OSPF configuration?
To specify the networks that OSPF should advertise
What is the purpose of the 'passive-interface' command in OSPF configuration?
To prevent OSPF from sending hellos on an interface
What is the effect of the 'no router bgp' command?
It disables BGP on a router
What is the purpose of the 'auto-cost reference-bandwidth' command in OSPF configuration?
To define the reference bandwidth for OSPF cost calculation
What is the purpose of the 'conf t' command?
To enter global configuration mode
What is the effect of the 'no router bgp' command?
Disables BGP routing on the router
What is the purpose of the 'write memory' command?
To save the configuration to the startup configuration
What is the purpose of the 'network' command in OSPF configuration?
To specify the networks that OSPF will advertise
What is the purpose of the 'router ospf' command?
To configure the OSPF process
What is the effect of the 'clear ip ospf' command?
Resets the OSPF process
What is the purpose of the 'passive-interface' command in OSPF configuration?
To suppress OSPF routing on the interface
What is the purpose of the 'write memory' command?
To save the configuration changes to the startup-config
What is the purpose of the 'conf t' command?
To enter the configuration mode
What is the effect of the 'no router ospf' command?
Disables OSPF routing on the router
What is the purpose of the 'no auto-summary' command in BGP configuration?
To disable automatic summarization of routes
What is the effect of the 'no bgp default ipv4-unicast' command?
It disables IPv4 unicast routing by default
What is the purpose of the 'neighbor' command in BGP configuration?
To configure a BGP neighbor
What is the purpose of the 'address-family' command in BGP configuration?
To specify the address family for a BGP neighbor
What is the purpose of the 'next-hop-self' command in BGP configuration?
To specify the next hop as the local router itself
What is the purpose of the 'update-source' command in BGP configuration?
To specify the source IP address of the BGP updates
What is the purpose of the 'send-community' command in BGP configuration?
To send community attributes to the BGP neighbor
What is the effect of the 'shut' command on an interface?
It disables the interface
What is the purpose of the 'auto-cost reference-bandwidth' command in OSPF configuration?
To set the reference bandwidth for cost calculation
Which command is used to configure the router to advertise OSPF routes into BGP?
redistribute ospf 10 match internal external 1 external 2
What is the purpose of the 'address-family ipv4 vrf' command in MP-BGP configuration?
To specify the VRF instance for MP-BGP
Which command is used to exit the address-family configuration mode in MP-BGP?
exit-address-family
What is the purpose of the 'redistribute bgp 9829 subnets' command in OSPF configuration?
To redistribute BGP routes into OSPF
Which command is used to configure the OSPF process for a CE-PE link?
router ospf 10 vrf ibm
What is the purpose of the 'network' command in OSPF configuration?
To specify the networks that OSPF will advertise
Which command is used to configure the BGP process for a VRF instance?
router bgp 9829 vrf ibm
Study Notes
Router Configurations
-
PUNE-PE Router Configuration:
- Enabled BGP with AS number 9829
- Configured neighbors 192.168.5.254 and 192.168.0.254 with remote AS 9829
- Configured update source for neighbors to loopback 0
- Disabled BGP default IPv4 unicast
- Configured address-family ipv4 vrf ibm and vrf sun
- Configured neighbors 172.16.16.70 and 172.16.16.6 with remote AS 10 and 40 respectively
- Configured next-hop-self for neighbors
- Configured address-family vpnv4 and activated neighbors
- Configured send-community both for neighbors
-
CHENNAI-PE Router Configuration:
- Enabled and disabled interfaces
-
IBM-CE-3 Router Configuration:
- Configured loopback 1 with IP address 10.30.0.1/16
- Enabled BGP with AS number 30
- Configured neighbors 172.16.16.65 with remote AS 9829
- Configured network 10.30.0.0/16 and 192.168.7.254/32
-
SUN-CE-1 and SUN-CE-2 Router Configurations:
- Removed OSPF 9829
- Disabled MPLS on interfaces
- Configured BGP 40 and created loopback 1 interface
- Configured neighbors 172.16.16.5 and 172.16.16.29 with remote AS 9829
- Configured network 20.40.0.0/16 and 192.168.6.254/32
- Configured controller and disabled MPLS on interfaces
Verification Commands
-
PUNE-PE Router:
- Show ip vrf
- Show ip vrf detail
- Show ip vrf interfaces
- Show ip protocols vrf ibm
- Show ip route vrf ibm
- Show ip bgp vpnv4 vrf ibm
- Show ip bgp vpnv4 vrf ibm neighbors
- Show ip bgp vpnv4 all summary
- Show ip bgp neighbors
- Show mpls forwarding vrf ibm
- Show ip cef vrf ibm
- Ping vrf ibm 10.20.0.1
- Trace vrf ibm 10.20.0.1
- Telnet 10.20.0.1 /vrf ibm
MPLS-VPN Configuration
-
MPLS-VPN Configuration using MP-BGP/OSPF Lab:
- Delhi-P and Mumbai-P: No configuration needed
- PUNE-PE: Configured OSPF process 10 for CE-PE link
-
MPLS-VPN Configuration using MP-BGP/Static Lab:
- Delhi-P and Mumbai-P: No configuration needed
- PUNE-PE:
- Removed OSPF process and configured static route
- Modified MP-BGP configuration
Removing OSPF and Configuring Default Route
- On IBM-CE-3, OSPF 30 was removed and a default route was configured using the command
ip route 0.0.0.0 0.0.0.0 Serial 4/0/0:0. - On SUN-CE-1 and SUN-CE-2, OSPF 40 and OSPF 50 were removed, and default routes were configured using the commands
ip route 0.0.0.0 0.0.0.0 pos 3/1respectively.
OSPF Configuration
- On IBM-CE-2, OSPF 20 was configured with the commands
router ospf 20,auto-cost reference-bandwidth 1000,network 172.16.16.12 0.0.0.3 area 0, andnetwork 10.20.0.0 0.0.255.255 area 0. - On IBM-CE-3, OSPF 30 was configured with the commands
router ospf 30,auto-cost reference-bandwidth 1000,network 172.16.16.64 0.0.0.3 area 0, andnetwork 10.30.0.0 0.0.255.255 area 0. - On SUN-CE-1, OSPF 40 was configured with the commands
router ospf 40,auto-cost reference-bandwidth 1000,network 172.16.16.4 0.0.0.3 area 0, andnetwork 20.40.0.0 0.0.255.255 area 0. - On SUN-CE-2, OSPF 50 was configured with the commands
router ospf 50,auto-cost reference-bandwidth 1000,network 172.16.16.16 0.0.0.3 area 0, andnetwork 20.50.0.0 0.0.255.255 area 0.
MP-iBGP/OSPF and MP-iBGP/Static/Default Configuration
- MP-iBGP/OSPF is used to handle huge traffic of routing updates learnt by Autonomous System Boundary Routers (ASBRs) from other Autonomous Systems.
- ASBRs of the same Autonomous System exchange global internet routing updates among themselves by running MP-iBGP directly between them without overloading other internal routers of that Autonomous System.
- OSPF is used as an interior gateway routing protocol (IGP) within an Autonomous System, but it cannot handle huge traffic, hence MP-iBGP is used instead.
Other Configurations
- On PUNE-PE, BGP 9829 was configured with various commands including
neighbor 192.168.5.254 remote-as 9829andaddress-family ipv4 vrf ibm. - On CHENNAI-PE, interfaces were enabled and disabled using the commands
int gi 2/1andshut. - On KOLKATA-PE, OSPF Process 20 was configured for CE-PE link using the command
router ospf 20 vrf ibm.
MPLS VPN Configuration
- MPLS Layer 3 VPNs provide an alternative to IPSec VPNs when supporting complex topologies.
- They solve the scalability issue of conventional IPSec VPNs deployed in a full-mesh model, reducing the configuration overhead while interconnecting many sites.
- Adding a new site to VPNs requires a single change on the Provider Edge (PE) device that connects the customer router.
MPLS VPN Architecture
- Customer Edge (CE) router peers with service provider's PE router using the IGP or eBGP, exchanging layer 3 routing information with the PE router.
- CE router has no VPN awareness.
- A VPN is formed between PE routers that run the Multiprotocol Extension for BGP-4 (MP-BGP), RFC 4760.
- MP-BGP is used for distributing customer prefixes within the provider's network.
MPLS VPN Operation
- Customer's data is switched in the service provider's Multiprotocol Label Switching (MPLS) network based on labels.
- Traffic follows through a predetermined label-switched path (LSP), which is an unidirectional tunnel between a pair of the PE routers.
MPLS VPN Configuration using MP-iBGP/eBGP, MP-iBGP/OSPF, and MP-iBGP/Static/Default
- Enabling and disabling interfaces and configuring controllers on PUNE-PE and other devices.
- Re-configuring OSPF 9829 and creating VPN (vrf-table) and assigning Route-distinguisher/Route-target.
- Disabling MPLS on interfaces not in the MPLS domain.
- Configuring MP-iBGP/eBGP, MP-iBGP/OSPF, and MP-iBGP/Static/Default on various devices.
Device Configuration
- PUNE-PE: configuring controller, re-configuring OSPF 9829, creating VPN, and disabling MPLS on interfaces.
- CHENNAI-PE: configuring MP-BGP and assigning route-target.
- IBM-CE-2: configuring OSPF 20 and removing BGP 20.
- IBM-CE-3: configuring OSPF 30 and removing BGP 30.
- SUN-CE-1: configuring OSPF 40 and removing BGP 40.
- SUN-CE-2: configuring OSPF 50 and removing BGP 50.
Removing OSPF and Configuring Default Route
- On IBM-CE-3, OSPF 30 was removed and a default route was configured using the command
ip route 0.0.0.0 0.0.0.0 Serial 4/0/0:0. - On SUN-CE-1 and SUN-CE-2, OSPF 40 and OSPF 50 were removed, and default routes were configured using the commands
ip route 0.0.0.0 0.0.0.0 pos 3/1respectively.
OSPF Configuration
- On IBM-CE-2, OSPF 20 was configured with the commands
router ospf 20,auto-cost reference-bandwidth 1000,network 172.16.16.12 0.0.0.3 area 0, andnetwork 10.20.0.0 0.0.255.255 area 0. - On IBM-CE-3, OSPF 30 was configured with the commands
router ospf 30,auto-cost reference-bandwidth 1000,network 172.16.16.64 0.0.0.3 area 0, andnetwork 10.30.0.0 0.0.255.255 area 0. - On SUN-CE-1, OSPF 40 was configured with the commands
router ospf 40,auto-cost reference-bandwidth 1000,network 172.16.16.4 0.0.0.3 area 0, andnetwork 20.40.0.0 0.0.255.255 area 0. - On SUN-CE-2, OSPF 50 was configured with the commands
router ospf 50,auto-cost reference-bandwidth 1000,network 172.16.16.16 0.0.0.3 area 0, andnetwork 20.50.0.0 0.0.255.255 area 0.
MP-iBGP/OSPF and MP-iBGP/Static/Default Configuration
- MP-iBGP/OSPF is used to handle huge traffic of routing updates learnt by Autonomous System Boundary Routers (ASBRs) from other Autonomous Systems.
- ASBRs of the same Autonomous System exchange global internet routing updates among themselves by running MP-iBGP directly between them without overloading other internal routers of that Autonomous System.
- OSPF is used as an interior gateway routing protocol (IGP) within an Autonomous System, but it cannot handle huge traffic, hence MP-iBGP is used instead.
Other Configurations
- On PUNE-PE, BGP 9829 was configured with various commands including
neighbor 192.168.5.254 remote-as 9829andaddress-family ipv4 vrf ibm. - On CHENNAI-PE, interfaces were enabled and disabled using the commands
int gi 2/1andshut. - On KOLKATA-PE, OSPF Process 20 was configured for CE-PE link using the command
router ospf 20 vrf ibm.
This quiz covers the configuration of BGP routing protocol on a Cisco router, including neighbor setup and address family configuration. Test your knowledge of BGP commands and syntax.
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