CIDR /31 and /32 in production: RFC 3021, point-to-point links, and host routes
CIDR /31 and /32 are often dismissed as "unusable sizes," but in real routing tables they appear constantly. This article unpacks RFC 3021''s redefinition of /31 for point-to-point links, /32 for loopbacks and host routes, container CNIs, and the L2/L3 gotchas.
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