Cisco's IOS calls it Administrative Distance, other vendors call it Default Preference, Distance, many vendors call it Priority. But what is this administrative distance?.

Administrative Distance or Priority is a networking operating system specific priority table for the supported routing protocols.

The protocol with the highest priority on this priority table, wins. The highest priority is in that case either 0 or 1 or a the smallest digit. Across all network operating systems in the overview below, the highest priority is always set to the directly connected network it is everywhere 0, or some kind of system or kernel route.

Here following acronyms would describe the following overview also good enough. These are my own ideas how it also could be named or described in short form cross-vendor:

  • NOSSDAD - Network Operating System Specific Default Administrative Distance
  • IDRPP - Implementation Dependent Routing Protocol Priority
📘 Note
The overview shown below are the default network operating system specific presets, default settings

AW+

Allied Telesis's AW+ - AlliedWare-plus - Administrative Distance Overview found in the Config basic OSPF routing configuration guide.

Protocol Administrative Distance
Connected 0
Static 1
EBGP 20
OSPF 110
RIP 120

ArubaOS

Aruba's (ArubaOS) Administrative distance is found on docs for the 3810 and 5400R series routers. Aruba 3810 / 5400R Multicast and Routing Guide for ArubaOS-Switch 16.08

Protocol Administrative Distance
Connected 1
Static 1
EBGP 20
OSPF 110
RIPng 120
iBGP 200
📘 Note
Administrative Distance for BGP not written or defined or named in the official documentation, it is only guessed here in the overview

B.I.R.D.

linux's () - Control Plane for linux IP routing. No official documentation found yet.

* Update *

Interesting note on the default preference behaviour from the mailing list says:

Note though that the preference value in bird is inverted compared to
Cisco which uses administrative distance. Juniper seems to use the term
preference value but have the same semantics as Cisco administrative
distance.

Bird preference value: higher is more preferred
Cisco/Juniper AD value: lower is more preferred

* Last update 2023 *

This is the last update regarding B.I.R.D.

  • B.I.R.D does not properly support the same route coming from multiple routing protocols; it's undefined behavior in B.I.R.D.
  • B.I.R.D.'s official documentation is lacking ANY examples on how to configure and handle B.I.R.D. with different vendors routing implementations.

If you find out a way how to configure and operate B.I.R.D. with different vendors please write me an email. I have been searching for simple configuration examples on this topic now for a long time. The usersbase could not hint me into the "right" direction. I still do not know how to configure B.I.R.D. and how to operate it in a multi vendor network environement.

Comware

HP's (ComWare) ComWare's preference

Protocol Preference
Direct route 0
Multicast static route 1
OSPF 10
IS-IS 15
Unicast static route 60
RIP 100
OSPF ASE 150
OSPF NSSA 150
IBGP 255
EBGP 255
Unknown (route from an untrusted source) 256

ComWare has the lowest preference on BGP compared with other implementations.

EXOS

ExtermeNetworks's (EXOS)

No online reference found yet. The output is taken from the EXOS cli. EXOS as the only network operating system has a protocol priorty range x > 256. The LOWEST priority is assigned to the *Bootp protocol to 5000. The directly connected network has a priority of 10, this is the highest priority setting.

exos# show iproute priority
Protocol Priority
Direct 10
MPLS 20
Blackhole 50
Static 1100
ICMP 1200
EBGP 1700
IBGP 1900
OSPFIntra 2200
OSPFInter 2300
Isis 2350
IsisL1 2360
IsisL2 2370
RIP 2400
OSPFAsExt 3100
OSPFExt1 3200
OSPFExt2 3300
IsisL1Ext 3400
IsisL2Ext 3500
Bootp 5000

FRR

linux's Free Range Routing (FRR) FRRouting - Administrative Distance

Protocol Distance
System 0
Kernel 0
Connect 0
Static 1
NHRP 10
EBGP 20
EIGRP 90
BABEL 100
OSPF 110
ISIS 115
OPENFABRIC 115
RIP 120
able 150
SHARP 150
IBGP 200
PBR 200

IOS/IOS-XE/IOS-XR/NX-OS

Cisco's - Internetwork Operating System (IOS) IOS/-XE/-XR/NX-OS - Administrative Distance

Protocol Administrative Distance
directly connected interface 0
static route 1
DMNR 3
EIGRP (summary route) 5
eBGP 20
EIGRP (internal route) 90
IGRP 100
OSPF 110
IS-IS 115
RIP 120
EGP 140
ODR 160
EIGRP (external route) 170
iBGP 200
Unknown 255

JUNOS

Juniper's (JUNOS) JUNOS - Default Preference

Protocol Default Preference
directly connected network 0
system route 4
static and Static LSP 5
Static LSP 6
RSVP-signaled LSP 7
LDP-signaled LSP 9
OSPF internal route 10
access-internal route 12
access route 13
IS-IS Level 1 internal route 15
IS-IS Level 2 internal route 18
Redirect 30
Kernel 40
SNMP 50
Router discovery 55
RIP 100
RIPng 100
PIM 105
DVMRP 110
Aggregate 130
OSPF AS external route 150
IS-IS Level 1 external route 160
IS-IS Level 2 external route 165
BGP 170
MSDP 175

LCOS

LANCOM's (LCOS) LCOS - Administrative Distance

># show admin-distance
Protocol/App Distance
Loopback 0
Local LAN 0
Local WAN 0
VRRP 0
Broadcast 0
Connected LAN 2
Connected WAN 2
DHCP Automode 4
Static 5
VPN 15
VPN-Mesh 15
PPP Server 15
464XLAT 15
DHCP 15
Autoconfig 15
Framed 15
CAPWAP 15
Rollout-Agent 15
eBGP 20
OSPF 110
RIP 120
iBGP 200
LISP 240
Automatic Default 254
Static Ifc Down 255

Command admin-distance, but the overview shows Distance.

RouterOS

MikroTik's (RouterOS) RouterOS - Route Distance

Protocol Distance
connected 0
static 1
eBGP 20
OSPF 110
RIP 120
MME 130
iBGP 200

What is MME? Mesh Made Easy a RouterOS/MikroTik routing protocol based on B.A.T.M.A.N..

SR OS

Nokia's - Service Router Operating System (SROS) Route Preference Defaults by Route Type

Protocol Preference
Direct attached 0
Static routes 5
OSPF internal 10
IS-IS level 1 internal 15
IS-IS level 2 internal 18
OSPF external 150
IS-IS level 1 external 160
IS-IS level 2 external 165
BGP 170

VRP

Huawei's - Versatile Routing Platform (VRP) Routing Protocol Preference

Protocol Default External Preference
Direct 0
OSPF 10
IS-IS Level-1 15
IS-IS Level-2 18
EBGP 20
Static 60
RIP 100
OSPF ASE 150
OSPF NSSA 150
IBGP 200

What is OSPF ASE? Did not find out yet. It might be some Stubby Area perhaps. No online documentation found. Interestingly, VRP has a much lower preference for static routes than any other implementations.