Which command must be run on a Cisco IOS device to configure six parallel iBGP...

Comprehensive and Detailed Explanation From Cisco SP Core Optimization Knowledge

Cisco IOS supportsBGP Multipathfor installing multiple equal-cost BGP routes (both iBGP and eBGP) into the routing table. The correct global BGP command syntax to set the number of allowable parallel BGP paths is:

maximum-paths

For BGP specifically, the form is:

maximum-paths bgp

This enables the router to install up to the specified number of equal-cost BGP routes (iBGP and eBGP) into the RIB and then potentially into the FIB.

Setting:

maximum-paths bgp 6

allowssixparallel ECMP paths learned via BGP—this matches the requirement in the question.

Why the other options are incorrect

B. multipath eibgp 6Not a valid Cisco IOS command.

C. maximum paths bgp routers 6Invalid syntax.

D. maximum-paths eibgp 6The correct keyword isbgp, noteibgp.Cisco does not use “eibgp” in this context; IOS supports BGP multipath across iBGP/eBGP automatically when configured under maximum-paths bgp.