dtaht / diffserv

An attempt to fully classify packets on a home router into diffserv

Definitive Packet Classifier

This is an attempt to fully implement rfc 4594, along with some proposed extensions, at the edge router on the home gateway. The results should be suitable also for hotels, convention centers and small businesses.

It could be further extended by supplying tables to end machines, to classify their behavior at the switch, rather than router level.

It is being tested within the auspices of the ‘uberwrt’ series of projects.

Requirements

Be both ipv6 and ipv4 enabled.

Handle packet encapsulation (VPN) traffic correctly

Components

Debloating Techniques

Minimize multicast

Short queue lengths

Use web proxies by default (wpad and dhcp supplied)

ECN Enabled

Optimizations for

Classifier

Shall include comprehensive port to dscp database.

Shall also include anti-worm filtering

Bandwidth Shaper(s) and policer(s)

The bandwidth shapers should be as simple as possible, but no simpler.

Example logic would include the number and type of machines in a household, the kinds of traffic the user expects, etc.

It would be good to allow for bandwidth sharing.

Should penalize

DSCP statistics

Complete DSCP statistics will be kept.

Wired and Wireless awareness

802.11e converter

Wherever possible, packets will be transformed into their proper 802.11e classes.

802.11d converter

Wherever possible, packets will be transformed into their proper 802.11d classes.

Futures

Simple lookup tables for DSCP <-> Port mappings

Simple lookup tables for threats

Support for multiple switch types and vlan prioritizations

Tasks Ahead

Write Good classifier

Analyze existing realistic traffic

Measure existing shapers

Implement ECN in existing shapers

diffserv's Issues

ANT DSCP

The ANT DSCP is used in scripts/functions.sh,
but it is not defined in scripts/codepoints.sh .

802.1Q PCP to 802.11 AC mapping

I think the 802.1Q PCP to 802.11 AC mappings are wrong.

In scripts/functions.sh and ame/functions.sh the mapping should be:

# const int ieee802_1d_to_ac[8] = {
#     IEEE80211_AC_BE,    // 0  BE
#     IEEE80211_AC_BK,    // 1  BK
#     IEEE80211_AC_BE,    // 2  EE
#     IEEE80211_AC_BI,    // 3  CA
#     IEEE80211_AC_VI,    // 4  VI
#     IEEE80211_AC_VO,    // 5  VO
#     IEEE80211_AC_VO,    // 6  IN
#     IEEE80211_AC_VO     // 7  NC
# };

In db/dscp.sql the mapping should be:

insert into d2e_map values (0,'BE',1,'BE');
insert into d2e_map values (1,'BK',0,'BK');
insert into d2e_map values (2,'EE',1,'BE');
insert into d2e_map values (3,'CA',2,'VI');
insert into d2e_map values (4,'VI',2,'VI');
insert into d2e_map values (5,'VO',3,'VO');
insert into d2e_map values (6,'IC',3,'VO');
insert into d2e_map values (7,'NC',3,'VO');

Where did the current mapping came from?

Documentation: Cisco

In the documentation Cisco is mentioned.
What you referring to is "Cisco's QoS Baseline".

RFC-4594 is based on Cisco's QoS Baseline.

For DSCP table see: RFC-4594 Section 2.3.
For differences between RFC-4594 and Cisco's QoS Baseline see:
http://www.cisco.com/en/US/docs/solutions/Enterprise/WAN_and_MAN/QoS_SRND_40/QoSIntro_40.html#wp60882

VA DSCP

The VA DSCP is missing.
VA = Voice Admit = 44 = 0b101100
See: RFC-5865 Section 4.

802.1Q Mapping

In scripts/functions.h : mac80211e() and ame/functions.h : mac8021q(), mac80211e()
CS1 DSCP (= Signalling DSCP Service Class) is mapped to a background priority.

The CS1 DSCP is placed in the IpTables Chain 'Ants' (comment: "VOIP Signalling").

Is the mapping from CS1 DSCP to IEEE 802.1Q PCP and IEEE 802.11e AC (WMM) correct?
If so, why is VoIP Signalling in IpTables an Ant and for IEEE 802.1Q PCP a background?

P2P DSCP in DB

The DSCP value for P2P in db/dscp.sql (33) and scripts/codepoints.sh (9) differ.

CA PCP

The IEEE 802.1Q PCP 'CA' (= Critical Application) is incorrectly named 'CR' in db/dscp.sql.
See: Table G-2 in IEEE 802.1Q-2005.