Menu

US Region

Grandmetric LLC
Lewes DE 19958
16192 Coastal Hwy USA
EIN: 98-1615498
+1 302 691 94 10
info@grandmetric.com

EMEA Region

GRANDMETRIC Sp. z o.o.
ul. Metalowa 5, 60-118 Poznań, Poland
NIP 7792433527
+48 61 271 04 43
info@grandmetric.com

UK

Grandmetric LTD
Office 584b
182-184 High Street North
London
E6 2JA
+44 20 3321 5276
info@grandmetric.com

  • en
  • pl
  • Static floating routing (Cisco)

    Design & Configure

    Static floating routing (Cisco)

    Technology: Routing

    Area: Static routing

    Vendor: Cisco

    Title: Floating Static Routing

    Software: 12.X , 15.X, IP Services

    Platform: Catalyst 3560, 3750, 3850, 4500, 6500, ISR/ASR Routers

     

    In situation when a router has two identical routes the decision regarding which one gets installed in the routing table is based on the lowest administrative distance. With static routing, we can deliberately use this behavior as a basic redundancy mechanism by configuring a backup route with
    a higher administrative distance than the primary route.

    To configure floating static routing you need to specify the backup route with higher administrative distance value in our case it is a number of 10:

    R1#configure terminal
    R1(config)#ip route 100.10.20.0 255.255.255.0 172.16.1.1
    R1(config)#ip route 100.10.20.0 255.255.255.0 10.1.0.2 10

     

    Verification commands:

    We can verify current state of our floating static route by using below command. The best path has an administrative distance equal one, however the non-active backup path has value of 10.

    R1#show ip static route 100.10.20.0/24
    Codes: M - Manual static, A - AAA download, N - IP NAT, D - DHCP,
    G - GPRS, V - Crypto VPN, C - CASA, P - Channel interface processor,
    B - BootP, S - Service selection gateway
    DN - Default Network, T - Tracking object
    L - TL1, E - OER, I - iEdge
    D1 - Dot1x Vlan Network, K - MWAM Route
    PP - PPP default route, MR - MRIPv6, SS - SSLVPN
    H - IPe Host, ID - IPe Domain Broadcast
    U - User GPRS, TE - MPLS Traffic-eng, LI - LIIN
    Codes in []: A - active, N - non-active, B - BFD-tracked, D - Not Tracked, P - permanent

    100.10.20.0/24 [1/0] via 172.16.1.1 [A]
    M                 [10/0] via 10.1.0.2 [N]

    Once in any reason the primary path goes done we can verify the network state with the same command and check if backup takes priority.

    R1#sh ip static route 100.10.20.0/24
    Codes: M - Manual static, A - AAA download, N - IP NAT, D - DHCP,
    G - GPRS, V - Crypto VPN, C - CASA, P - Channel interface processor,
    B - BootP, S - Service selection gateway
    DN - Default Network, T - Tracking object
    L - TL1, E - OER, I - iEdge
    D1 - Dot1x Vlan Network, K - MWAM Route
    PP - PPP default route, MR - MRIPv6, SS - SSLVPN
    H - IPe Host, ID - IPe Domain Broadcast
    U - User GPRS, TE - MPLS Traffic-eng, LI - LIIN
    Codes in []: A - active, N - non-active, B - BFD-tracked, D - Not Tracked, P - permanent

    M  100.10.20.0/24 [1/0] via 172.16.1.1 [N]
    M                 [10/0] via 10.1.0.2 [A]

    Author: Marcin Bialy
     
    Grandmetric