diff --git a/acronyms.tex b/acronyms.tex
index e2323e1..0b4c16f 100644
--- a/acronyms.tex
+++ b/acronyms.tex
@@ -171,6 +171,7 @@
 \newacronym{ula}{ULA}{Unique Local Address}
 \newacronym{utc}{UTC}{Coordinated Universal Time}
 \newacronym{vlan}{VLAN}{Virtual Local Area Network}
+\newacronym{vlsm}{VLSM}{Variable-Length Subnet Masking}
 \newacronym{vpn}{VPN}{Virtual Private Network}
 \newacronym{vrf}{VRF}{Virtual Routing and Forwarding}
 \newacronym{vrrp}{VRRP}{Virtual Router Redundancy Protocol}