Border Gateway Protocol with MikroTik
Order
1
Attribute
Next Hop
Validation
2
3
Weight
Local preference
4
Shortest AS Path
5
6
Locally Originated
Origin
7
MED
8
eBGP or iBGP
9
Router ID
10
Route Reflector
Cluster List
11
Neighbor Address
BGP Best Path Selection Algorithm in RouterOS
Description
Default Value
The route is evaluated by the
algorithm only if it is valid. In
general, the route is considered valid
if:
*NEXT_HOP of the route is valid and
The 1st Valid
reachable
route is accepted.
*AS_PATH received from external
Other valid routes
peers does not contain the local AS
are then
*The route is not rejected by routing
compared to the
filters
1st one.
This parameter is not a part of the
BGP standard, it is invented to quickly
and locally select the best route. This
parameter is local to the router
(assigned with routing filters in the
BGP input) and cannot be advertised.
Only within an AS
Skipped if ignore-as-path is set
Each AS set counts as 1
Prefer the path that was locally
originated via aggregate or BGP
network
Lowest (IGP < EGP < INCOMPLETE)
Prefer the path with the lowest multiexit discriminator (MED).
The router compares the MED
attribute only for paths that have the
same neighboring (leftmost) AS. Paths
without explicit MED value are
treated with MED of 0.
Evaluate IGP metrics (Prefer eBGP
over iBGP)
Use lowest; if route carries Originator
ID, use that instead.
Prefer the route with the
shortest route reflection cluster list.
Routes without a cluster list are
considered to have a cluster list of
length 0.
Prefer the path from the lowest
neighbor address
0
100
N/A
N/A
N/A
iBGP
eBGP
X
X
X
X
X
N/A
X
X
X
X
X
X
N/A
X
X
X
X
X
X
N/A
X
X
0
N/A
Lowest IP address
or Router ID, if set
0
N/A
Border Gateway Protocol with MikroTik
Default Scope & Target Scope
Route
Target
Scope
Type
Scope
Connected
10 Active
N/A
20
30
40
40
OSPF, RIP
MME
Static
eBGP
iBGP
10
10
10
30
Connected
20 inactive
Default Route
Distances
Connected
Static
eBGP
OSPF
RIP
MME
iBGP
0
1
20
110
120
130
200
N/A
Routing Protocol
RIPv1
RIPv2
RIP-NG
OSPFv2
OSPFv3
BGP
Type
Protocols Supported
Distance
Vector
IPv4
Distance
Vector
IPv4
Distance
Vector
IPv6
Link State
IPv4
Link State
IPv6
Metric
Metric
Protocol Used
UDP Port 520
Metric
UDP Port
520
Metric
UDP Port
521
Cost & Metric
IP Protocol
#89
Cost & Metric
IP Protocol
#89
Path Vector
IPv4&6
Multiple
metrics
Multicast Address
Classful or Classless Routing
255.255.255.255 224.0.0.9
Classful Routing CIDR
FF02::9
CIDR
224.0.0.5
224.0.0.6
CIDR
FF02::5
CIDR
TCP Port 179
N/A
CIDR