Why did the queueing default change from WFQ to FIFO in IOS 11.2?

[rjackson]

Hi,

I'm looking for an explanation of why the IOS starting using fifo queueing instead of weighted fair around version 11.2. Seems like that was when traffic shaping started so I guess there might be a connection there but I dont know what it is. What happens if I turn WFQ back on? Does traffic shaping work under WFQ?

Is there a reference out there that explains the change?

[rsissons]

It is the other way round. WFQing is the default in all current levels of IOS and I believe that was introduced in 11.2.

The change was in an effort to improve throughput.

[rjackson]

Thats what everyone seems to think but when I paste this config into a 2610 running 12.0

hostname Michaels-2712

.

!

service timestamps debug datetime

service timestamps log datetime

service password-encryption

no ip domain-lookup

.

.

.

!

interface Serial0/0

no ip address

encapsulation frame-relay

no shutdown

!

interface Serial0/0.1 point-to-point

ip address 10.120.24.170 255.255.255.248

frame-relay interface-dlci 950

no shutdown

I get this. These "no fair queue" statements are in over 700 routers and we didn't put them there.

Michaels-2712#sh conf

Using 1926 out of 29688 bytes

!

version 12.0

service timestamps debug datetime

service timestamps log datetime

service password-encryption

!

hostname Michaels-2712

!

logging buffered 4096 debugging

enable secret 5 $1$nx.X$6rXDieeDpEJ5Gp5Rpz2Jd/

!

username RAS1 password 7 04480E051A3349

ip subnet-zero

no ip domain-lookup

chat-script rset-usr "" AT&F1 OK AT&B1 OK AT&U10 OK AT&N14

!

!

!

interface Ethernet0/0

ip address 10.127.148.62 255.255.255.192

no ip directed-broadcast

!

interface Serial0/0

no ip address

no ip directed-broadcast

encapsulation frame-relay

no ip mroute-cache

no fair-queue

!

interface Serial0/0.1 point-to-point

ip address 10.120.24.170 255.255.255.248

no ip directed-broadcast

It changed at 11.2 but I cannot find out why.