Hi,
I’m trying to set up a Diffserv test bed and having a few problems. Bellow is
the summary
Experiment:
Diffserv Test Bed.
Aim:
To validate that expedited forwarding per-hop-behaviors is able to provide a
guaranteed bandwidth together with a very small delay and jitter even in a
highly congested network.
Environment:
5 Work stations
Fore ground and background and receiver workstation: PIII
Core and Edge routers: PII, 128 Megs
All installed with Red Hat8, kernel 2.4.18.-14
QoS modules are configured as modules
Network layout:
Please see attached diagram
Traffic generation using Iperf sending to 2 different ports on the receiver work
station, 5001 and 4000. Priority traffic is marked with the value of 0xb8 using
Iperf
Scripts:
Following scripts are running on the Core and Edge router.
#!/bin/sh
#
# Diffserv Core device: EF using CBQ
# Clear the existing qdisc configuration
tc qdisc del dev eth1 root
# Attach DSMARK qdisc to root and copy TOS byte into skb->tc_index
tc qdisc add dev eth1 handle 1:0 root dsmark indices 64 set_tc_index
# Add filter to root to mask out ECN bits and
# Extract the DSCP field by shifting to the right two bits
# ________
# TOS / /\
# 0xb8 -> | 10111000
# | ||||||
# \/vvvvvv DSCP
# 00101110 -> 0x2e
#
tc filter add dev eth1 parent 1:0 \
protocol ip prio 1 tcindex mask 0xfc shift 2
# Attach classful CBQ qdisc to 2:0 (2:0 is a child of root node 1:0)
tc qdisc add dev eth1 parent 1:0 handle 2:0 cbq \
bandwidth 10Mbit cell 8 avpkt 1000 mpu 64
# -------------------------
# EF Class (2:1)
# -------------------------
# CBQ bounded and isolated at EF Rate
tc class add dev eth1 parent 2:0 classid 2:1 cbq \
bandwidth 10Mbit rate 2000Kbit avpkt 1000 prio 1 \
bounded isolated allot 1514 weight 1 maxburst 10
# PFIFO buffer management scheme
tc qdisc add dev eth1 parent 2:1 pfifo limit 5
tc filter add dev eth1 parent 2:0 protocol ip prio 1 \
handle 0x2e tcindex classid 2:1 pass_on
# -------------------------
# BE class (2:2)
# -------------------------
# CBQ with borrow
tc class add dev eth1 parent 2:0 classid 2:2 cbq \
bandwidth 10Mbit rate 4Mbit avpkt 1000 prio 7 \
allot 1514 weight 1 maxburst 21 borrow split 2:0 defmap 0xffff
# RED buffer management scheme
tc qdisc add dev eth1 parent 2:2 red limit 60KB min 15KB max 45KB \
burst 20 avpkt 1000 bandwidth 10Mbit probability 0.4
tc filter add dev eth1 parent 2:0 protocol ip prio 2 \
handle 0 tcindex mask 0 classid 2:2 pass_on
-----------------------------------------------------------------------
Script running on the Edge device
# Diffserv Edge device: EF using CBQ
tc qdisc del dev eth1 root
tc qdisc add dev eth1 handle 1:0 root cbq \
bandwidth 10Mbit cell 8 avpkt 1000 mpu 64
tc class add dev eth1 parent 1:0 classid 1:1 cbq \
bandwidth 10Mbit rate 3000Kbit avpkt 1000 prio 1 \
bounded isolated allot 1514 weight 1 maxburst 10
tc class add dev eth1 parent 1:0 classid 1:2 cbq \
bandwidth 10Mbit rate 5Mbit avpkt 1000 prio 7 \
allot 1514 weight 1 maxburst 21 borrow split 1:0 defmap 0xffff
tc filter add dev eth1 parent 1:0 protocol ip prio 1 u32 \
match ip src 192.168.1.0/24 \
match ip dport 5001 16 \
police rate 3Mbit burst 20K drop \
flowid 1:1
tc filter add dev eth1 parent 1:0 protocol ip prio 2 u32 \
match ip src 192.168.1.0/24 \
flowid 1:2
tc qdisc add dev eth1 parent 1:2 handle 70:0 dsmark indices 64
tc qdisc add dev eth1 parent 1:1 handle 50:0 dsmark indices 64
tc class change dev eth1 classid 50:0 dsmark mask 0x3 value 0xb8
tc class change dev eth1 classid 70:0 dsmark mask 0x3 value 0x00
tc qdisc add dev eth1 parent 50:0 pfifo limit 5
tc qdisc add dev eth1 parent 70:0 red \
limit 60KB min 15KB max 45KB burst 20 \
avpkt 1000 bandwidth 10Mbit probability 0.4
Problem:
When enable the Diffserv by running the corresponding tc scripts on Edge and
Core router, it appeared that there was very high packet lost and no bandwidth
guarantee has taken place.
Checked:
Compiled tc with Diffserv enabled
Used the kernel with #define PSCHED_CLOCK_SOURCE PSCHED_CPU in
linux/include/net/sched/pkt_sched.h
Used the kernel with #define Hz 1500 in linux/include/asm/param.h
Your help is greatly appreciated.
Vince
UTS CRICOS Provider Code: 00099F
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