diff --git a/code/lspgen/src/lspgen_lsdb.h b/code/lspgen/src/lspgen_lsdb.h
index 6a65c0dc..20239f6a 100644
--- a/code/lspgen/src/lspgen_lsdb.h
+++ b/code/lspgen/src/lspgen_lsdb.h
@@ -305,7 +305,7 @@ typedef struct lsdb_attr_ {
 } lsdb_attr_t;
 
 #define MAX_OSPF_PACKET  1000 /* 16384 * 1000 bytes total LSA advertisement size */
-#define MAX_ISIS_FRAGMENT 256 /*  1465 *  256 bytes total LSP advertisement size */
+#define MAX_ISIS_FRAGMENT 256 /*  1462 *  256 bytes total LSP advertisement size */
 
 /*
  * An serialized LSA/LSP hanging off a node.
diff --git a/code/lspgen/src/lspgen_packet.c b/code/lspgen/src/lspgen_packet.c
index 2297159a..98961a20 100644
--- a/code/lspgen/src/lspgen_packet.c
+++ b/code/lspgen/src/lspgen_packet.c
@@ -1731,7 +1731,7 @@ lspgen_should_start_new_packet (lsdb_ctx_t *ctx, struct lsdb_packet_ *packet, st
     switch (ctx->protocol_id) {
     case PROTO_ISIS:
 	min_len =+ TLV_OVERHEAD;
-        if (packet->buf[0].idx > (1465-min_len)) {
+        if (packet->buf[0].idx > (1462-min_len)) {
 	    return true;
 	}
 	break;