An MPLS network infrastructure of the service provider ABC is growing very quickly due to many recent acquisitions.
Concerns arise about labeling each and every IP address on the service provider core network.
The IP address pace is designed as per following: -> Service provide ip address range is: 10.0.0.0/16 -> All loopbacks addresses use subnet mask /32 -> 10.0.0.0/24 range is used for loopback addresses -> All other subnet masks used for links are /24 and /25 Which configuration does significantly reduce the label allocations without compromising LDP functionalities?
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A. B. C. D.D.
The goal is to reduce the number of labels required in an MPLS network infrastructure of service provider ABC while preserving LDP functionality. This is achieved by minimizing the number of IP prefixes that are labeled in the network.
Option A:
ip prefix-list List1 deny 10.0.0.0/16 le 20 ge 25 mpls ldp label allocate global prefix-list List1
Explanation: This option configures a prefix-list to exclude certain IP address ranges from being labeled, and then enables global label allocation based on this prefix-list. The prefix-list denies any prefix that falls within the range of 10.0.0.0/16 with subnet masks between /20 and /25. This means that all subnets with a larger mask, such as /24 and /25, are included in the label allocation. However, this option may not be optimal since it excludes a large portion of the service provider's IP address space, which may cause connectivity issues in the future.
Option B:
access-list 1 permit 10.0.0.0.0.0.255.255 mpls ldp neighbor 10.0.0.1 labels accept 3
Explanation: This option uses an access-list to permit only one IP address range, 10.0.0.0/16, and configures the label allocation for a specific LDP neighbor. This option limits the number of labeled prefixes in the network, but it only applies to one neighbor and does not reduce the overall number of labeled prefixes in the network.
Option C:
mpls ldp password required for 10 access-list 10 permit 10.0.0.1 access-list 10 permit 10.0.0.2 access-list 10 permit 10.0.0.3
Explanation: This option adds security to the LDP protocol by requiring a password for all LDP sessions that use an IP address in the range of 10.0.0.0/16. It also configures access-lists to permit specific IP addresses for LDP sessions. This option does not reduce the number of labeled prefixes in the network.
Option D:
mpls ldp label allocate global host-routes
Explanation: This option configures the label allocation to use only host routes, which means that only loopback addresses (/32 prefixes) are labeled. This significantly reduces the number of labeled prefixes in the network, while preserving LDP functionality. However, this option may not be optimal since it does not label any non-loopback addresses, which may cause connectivity issues in the future.
In conclusion, the option that significantly reduces the label allocations without compromising LDP functionalities is Option D, "mpls ldp label allocate global host-routes".