cancel
Showing results for 
Search instead for 
Did you mean: 
cancel
620
Views
10
Helpful
4
Replies

Balanced scenario with two static routes without administrative distance.

Alex Deiwor
Level 1
Level 1

Hi,

 

I'm configuring a 3750 switch with a ISP provider using MHSRP on its side. Actually I'm using two GigaEthernet connections.

I wanna create load balancing from my side using static routes but the traffic flows I see are not equal neither similar.

 

router# show run | begin iproute

[...]

ip route 10.0.0.0 255.255.0.0 10.255.255.1
ip route 10.0.0.0 255.255.0.0 10.255.255.6

[...]

 

router# show ip route

[...]
S*    0.0.0.0/0 [1/0] via 192.168.0.254
      10.0.0.0/16 is variably subnetted, 23 subnets, 5 masks
S        10.0.0.0/16 [1/0] via 10.255.255.6
                    [1/0] via 10.255.255.1

[...]

 

By the way ip cef is already activated

 

This is the result:

Interface 1

GigabitEthernet1  is up, line protocol is up (connected)

[...]

  Queueing strategy: fifo
  Output queue: 0/40 (size/max)
  5 minute input rate 35046000 bits/sec, 4638 packets/sec
  5 minute output rate 8671000 bits/sec, 3846 packets/sec

 

Interface 2

GigabitEthernet2 is up, line protocol is up (connected)
[...]
  Queueing strategy: fifo
  Output queue: 0/40 (size/max)
  5 minute input rate 1000 bits/sec, 2 packets/sec
  5 minute output rate 3859000 bits/sec, 1714 packets/sec

 

IP CEF:

router#show ip cef
Prefix               Next Hop             Interface
10.0.0.0/16           10.255.255.1         Vlan99
                     10.255.255.6         Vlan99

 

I have no more configuration on the interfaces. Shall I add ip load balacing per packet instruction?

1 Accepted Solution

Accepted Solutions

Mark Malone
VIP Alumni
VIP Alumni

By default cef uses per destination load balancing , set ip load balancing per packet  on the gig links try again , are your links equal to up  10 network each side

View solution in original post

4 Replies 4

Mark Malone
VIP Alumni
VIP Alumni

By default cef uses per destination load balancing , set ip load balancing per packet  on the gig links try again , are your links equal to up  10 network each side

Ali Gheidarpour
Level 1
Level 1

CEF provides per destination load balancing, In per-destination mode all packets for a given destination are forwarded along the same path. Per-packet load balancing guarantees equal load across all links, however potentially the packets may arrive out-of-order at the destination as differential delay may exist within the network.

Regards

Ali Gheidarpour

Thank you both for that explanations.

Disclaimer

The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

Liability Disclaimer

In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.

Posting

I just wanted to touch upon what Ali has already mentioned, using per-packet load balancing may result in out-of-order packet arrival.  Although IP doesn't guarantee packet delivery sequence, intentionally setting yourself up for out-of-sequence delivery, can be very injurious to your application traffic.  I.e. it's often much better to allow the less than ideal link balancing to avoid out-of-sequence packet delivery.

Getting Started

Find answers to your questions by entering keywords or phrases in the Search bar above. New here? Use these resources to familiarize yourself with the community:

Innovations in Cisco Full Stack Observability - A new webinar from Cisco