doc: Add some more documentation about Notification support for GR

Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org>

diff --git a/doc/user/bgp.rst b/doc/user/bgp.rst
index 06fdc5f87f4d1940b78ada218bf1f2c7dcd57e55..3069745723ea52cb37973f741e70eea606d9fa96 100644 (file)
--- a/doc/user/bgp.rst
+++ b/doc/user/bgp.rst
@@ -967,6 +967,13 @@ However, it MUST defer route selection for an address family until it either.
    After changing this parameter, you have to reset the peers in order to advertise
    N-bit in Graceful Restart capability.
 
+   Without Graceful-Restart Notification capability (N-bit not set), GR is not
+   activated when receiving CEASE/HOLDTIME expire notifications.
+
+   When sending ``CEASE/Administrative Reset`` (``clear bgp``), the session is closed
+   and routes are not retained. When N-bit is set and ``bgp hard-administrative-reset``
+   is turned off Graceful-Restart is activated and routes are retained.
+
    Enabled by default.
 
 .. _bgp-per-peer-graceful-restart: