Introduction to Linux Advanced Routing and Traffic Management

Rafal Maszkowski <rzm@icm.edu.pl>

Budapest, August 2000

the tools - ipchains/iptables

• fwmark
• TOS changing
• copying to user space

the tools - ip command

• link, address - ifconfig
• neighbor - arp
• route - with multiple tables

ip route add 10.1/16 via 192.168.1.1 src 10.2.2.1
ip route add unreachable 10.1.2/24

• rule - routing tables management, routing keys: src, dst, tos, iif, fwmark
• tunnel - sit(ipv6-in-ipv4), gre, ipip (ipv4-in-ipv4, for uni- and multicasting)
• more...

the tools - tc command

• communicating with the kernel via netlink (as ip cmd)
• qdisc: CBQ, CSZ, PRIO, RED, SFQ, TBF
• class: CBQ
• filter: FW (fwmark), U32, ...

example of CBQ+U32+TBF

example - basic configuration

To note: single class-filter-queue, next can have id 10:3, filter added without a handle, units.

 

tc qdisc add dev eth0 root handle 10: cbq bandwidth 9765Kbit avpkt 1000 cell 8
tc class add dev eth0 parent 10:0 classid 10:1 cbq bandwidth 9765Kbit rate 9765Kbit allot 1514 cell 8 weight 976Kbit prio 8 maxburst 20 avpkt 1000

tc class add dev eth0 parent 10:1 classid 10:2 cbq bandwidth 9765Kbit rate 200000 allot 1514 cell 8 weight 20000 prio 5 maxburst 20 avpkt 1000
tc qdisc add dev eth0 parent 10:2 tbf rate 200000 buffer 1000000/8 limit 1300000 mtu 1500 peakrate 1000000
tc filter add dev eth0 parent 10:0 protocol ip prio 100 u32 match ip  dst 10.0.0.1 flowid 10:2

tc class replace dev eth0 parent 10:1 classid 10:2 cbq bandwidth 9765Kbit rate 100000 allot 1514 cell 8 weight 10000 prio 5 maxburst 20 avpkt 1000
tc qdisc del dev eth0 parent 10:2 tbf rate 200000 buffer 1000000/8 limit 1300000 mtu 1500 peakrate 1000000
tc qdisc add dev eth0 parent 10:2 tbf rate 100000 buffer 1000000/8 limit 1300000 mtu 1500 peakrate 1000000

tbf measurement

example - adding and changing filter

root@rzm:,0# tc filt show dev eth0
filter parent 10: protocol ip pref 100 u32
filter parent 10: protocol ip pref 100 u32 fh 800: ht divisor 1
filter parent 10: protocol ip pref 100 u32 fh 800::800 order 2048 key ht 800 bkt 0 flowid 10:2
 match 0a000001/ffffffff at 16
filter parent 10: protocol ip pref 100 u32 fh 800::801 order 2049 key ht 800 bkt 0 flowid 10:3
 match 0a000002/ffffffff at 16
...

(why 'at 16')

Delete one (and only one - use handle):

root@rzm:,1# tc filt del dev eth0 parent
10:0 protocol ip prio 100 handle 800::800 u32 match ip dst 10.0.0.1 flowid 10:2

Add with the same handle (next handle otherwise, up to 4K unique handles):

root@rzm:,0# tc filt add dev eth0 parent
10:0 protocol ip prio 100 handle 800::800 u32 match ip dst 10.0.0.1 flowid 10:2

root@rzm:,0# tc filt show dev eth0
filter parent 10: protocol ip pref 100 u32
filter parent 10: protocol ip pref 100 u32 fh 800: ht divisor 1
filter parent 10: protocol ip pref 100 u32 fh 800::800 order 2048 key ht 800 bkt 0 flowid 10:2
 match 0a000001/ffffffff at 16
filter parent 10: protocol ip pref 100 u32 fh 800::801 order 2049 key ht 800 bkt 0 flowid 10:3
 match 0a000002/ffffffff at 16
...


the tools - cbq.init




cbq.init: ftp://ftp.equinox.gu.net/pub/linux/cbq/, ftp://sunsite.icm.edu.pl/private/rzm/cbq.init/

configuration:


DEVICE=eth0,9765Kbit,976Kbit
RATE=10KBps
WEIGHT=1KB
PRIO=5
RULE=10.0.0.1
BUFFER=1000KB/8
LIMIT=1300KB
PEAK=250KBps



documentation




ipchains: man and http://www.linuxdoc.org/HOWTO/IPCHAINS-HOWTO.html

iptables/netfilter: man and http://netfilter.kernelnotes.org/unreliable-guides/packet-filtering-HOWTO.html

Advanced Linux routing HOWTO: http://www.linuxdoc.org/HOWTO/Adv-Routing-HOWTO.html

about ip command: http://snafu.freedom.org/linux2.2/iproute-notes.html,
http://snafu.freedom.org/linux2.2/docs/ip-cref/

cbq.init: at the beginning of the script

ip and tc in Polish: http://cbq.linux.pl/

incomplete documentation:

tc (help and some incomplete descriptions)

traffic control with netlink (tc source)








About this document ...

 Introduction to Linux Advanced Routing and Traffic Management

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The translation was initiated by Rafa³ Maszkowski on 2000-08-25