Commit 44bb019dc0 for frr

commit 44bb019dc07dfb11ac6b9e45d333a1b9a92ccd6b
Author: Andrei-Alexandru Bleortu <andrei@irix.systems>
Date:   Fri Oct 30 14:26:44 2026 +0200

    tests: fragment r2's LSP in isis_flex_algo_lan again

    Since an extended IS reachability is packed by its own size (#23842),
    r2's whole LSP is 248 bytes and fits in one fragment at lsp-mtu 260, so
    test_fragmented_lsp fails on master on every run: "r2's LSP is not
    fragmented". The two PRs passed CI separately and merged a minute apart.

    Use lsp-mtu 180. The prefix SIDs leave fragment zero from 220 down to
    160; below that, the LAN's extended IS reachability with its TE
    sub-TLVs fits no fragment and r2 originates an empty LSP. With
    participation checked per fragment again, the test still fails: r1
    drops label 16102.

    Signed-off-by: Andrei-Alexandru Bleortu <andrei@irix.systems>

diff --git a/tests/topotests/isis_flex_algo_lan/test_isis_flex_algo_lan.py b/tests/topotests/isis_flex_algo_lan/test_isis_flex_algo_lan.py
index e9be0d756e..998eb2567b 100644
--- a/tests/topotests/isis_flex_algo_lan/test_isis_flex_algo_lan.py
+++ b/tests/topotests/isis_flex_algo_lan/test_isis_flex_algo_lan.py
@@ -112,7 +112,9 @@ def test_fragmented_lsp():

     step("Fragment r2's LSP so that its prefix SIDs leave fragment zero")
     runs = _spf_runs(r1)
-    r2.vtysh_cmd("configure terminal\nrouter isis TEST\nlsp-mtu 260")
+    # r2's whole LSP is 248 bytes; at 180 its largest item, the LAN's
+    # extended IS reachability with its TE sub-TLVs, still fits a fragment.
+    r2.vtysh_cmd("configure terminal\nrouter isis TEST\nlsp-mtu 180")

     def _fragmented():
         lsp = r1.vtysh_cmd("show isis database detail r2.00-00")