From: Chris (clarson52@comcast.net)
Date: Wed Dec 10 2003 - 12:18:19 GMT-3
I was in a hurry...should read:
and IP Precedence only having 8 values
(0 - 7) each class would only have 1 or 2 priorities
I was in a rush.
Thank you Michael for pointing it out!! I appreaciate it.
----- Original Message -----
From: "Chris Larson" <clarson52@comcast.net>
To: "Michael Snyder" <msnyder@revolutioncomputer.com>;
<ccielab@groupstudy.com>
Cc: <swm@emanon.com>
Sent: Wednesday, December 10, 2003 8:28 AM
Subject: Re: Set Router Telnet Traffic to DSCP EF
> DSCP is also usefull to provide deifferentiation within classes. For
> instance if you were to follow Cisco's relative priority model of
> application classification they recommend something like:
>
> Gold
> Silver
> Best-Effort
> Less then best effort
>
> With 3 to 4 apps maximum within the each of the classes (at least the
> premium classes should only have 3 or 4 max) and TOS only having 8 values
> (0 - 7) each class would only have 1 or 2 ToS values as a differentiator.
> With DSCP, the Gold class could have 3 or 4 apps in it and each app would
> have a precedence within the class allowing them to be weighted within the
> class. Same with silver, best effort and kazza...I mean less then best
> effort.
>
> Especially less then best effort. We don't want to assign all less then
best
> effort traffic a ToS of 0. We do not want to treat Kazza or limewire and
our
> backups the same. We want backups and kazza to both be less then best
effort
> but our backups will probably be at the top within the less then best
effort
> class with all the other stuff having a value less then the backups within
> that class.
>
>
>
>
>
> ----- Original Message -----
> From: "Michael Snyder" <msnyder@revolutioncomputer.com>
> To: <ccielab@groupstudy.com>
> Cc: <swm@emanon.com>
> Sent: Wednesday, December 10, 2003 2:38 AM
> Subject: Set Router Telnet Traffic to DSCP EF
>
>
> > One of the first things that came up after I learned the relationship
> > between (Precedence TOS) and DSCP, was Scott Morris asking me what I
> > would use it for. After thinking about it, I came up with a lab
> > requirement that has a real world use!
> >
> > Requirement - Router originated telnet traffic should have a dscp of EF.
> >
> > Kicker - Do this without using any interface commands.
> >
> > Solution -
> >
> > R7
> >
> > ip local policy route-map setdscp
> > !
> > access-list 100 permit tcp any any eq telnet
> >
> > route-map setdscp permit 10
> > description EF bit pattern 101 110 = P5 T12
> > match ip address 100
> > set ip precedence critical
> > set ip tos 12
> >
> > Proof of Working Solution
> >
> > R8 (with dscp acl I have posted at end of email.)
> >
> > interface Serial0
> > ip address 150.50.101.2 255.255.255.252
> > ip access-group 110 in
> > ip router isis
> > encapsulation ppp
> > no peer neighbor-route
> > no fair-queue
> > service-module 56k clock source internal
> >
> >
> > R8#clear access-list counters
> >
> > R8#show access-lists
> > Extended IP access list 110
> > permit ip any any dscp default
> > permit ip any any dscp 1
> > permit ip any any dscp 2
> > permit ip any any dscp 3
> > permit ip any any dscp 4
> > permit ip any any dscp 5
> > permit ip any any dscp 6
> > permit ip any any dscp 7
> > permit ip any any dscp cs1
> > permit ip any any dscp 9
> > permit ip any any dscp af11
> > permit ip any any dscp 11
> > permit ip any any dscp af12
> > permit ip any any dscp 13
> > permit ip any any dscp af13
> > permit ip any any dscp 15
> > permit ip any any dscp cs2
> > permit ip any any dscp 17
> > permit ip any any dscp af21
> > permit ip any any dscp 19
> > permit ip any any dscp af22
> > permit ip any any dscp 21
> > permit ip any any dscp af23
> > permit ip any any dscp 23
> > permit ip any any dscp cs3
> > permit ip any any dscp 25
> > permit ip any any dscp af31
> > permit ip any any dscp 27
> > permit ip any any dscp af32
> > permit ip any any dscp 29
> > permit ip any any dscp af33
> > permit ip any any dscp 31
> > permit ip any any dscp cs4
> > permit ip any any dscp 33
> > permit ip any any dscp af41
> > permit ip any any dscp 35
> > permit ip any any dscp af42
> > permit ip any any dscp 37
> > permit ip any any dscp af43
> > permit ip any any dscp 39
> > permit ip any any dscp cs5
> > permit ip any any dscp 41
> > permit ip any any dscp 42
> > permit ip any any dscp 43
> > permit ip any any dscp 44
> > permit ip any any dscp 45
> > permit ip any any dscp ef (42 matches)
> > permit ip any any dscp 47
> > permit ip any any dscp cs6
> > permit ip any any dscp 49
> > permit ip any any dscp 50
> > permit ip any any dscp 51
> > permit ip any any dscp 52
> > permit ip any any dscp 53
> > permit ip any any dscp 54
> > permit ip any any dscp 55
> > permit ip any any dscp cs7
> > permit ip any any dscp 57
> > permit ip any any dscp 58
> > permit ip any any dscp 59
> > permit ip any any dscp 60
> > permit ip any any dscp 61
> > permit ip any any dscp 62
> > permit ip any any dscp 63
> > R8#
> >
> >
> > So using a route-map with the ip local policy, we can set any dcsp for
> > router traffic as we wish. VPN, Voice, Rip, Ping all comes to mind.
> > Not sure all those protocols have DSCP bits, but if they do, we can set
> > them.
> >
> > What is the relation ship between DSCP and Precedence-TOS?
> >
> > Well, dscp is a 6 bit value, to covert it we need to pad it with a
> > leading zero and ending zero to the value. I'll do it step by step.
> >
> > 1) ef expedited forwarding bit pattern 101110
> >
> > Prepend and append a zero to bring it to eight bits.
> >
> > 2) 0101 1100
> >
> > Now read the first four bits in hex, that's the Precedence.
> > Read the second four bits in hex, that is the TOS.
> >
> > 3) 0x5= decimal 5, 0xC= decimal 12
> >
> > Now just plug them into the route-map
> >
> > R7(config)#route-map setdscp permit 10
> > R7(config-route-map)#set ip pr
> > R7(config-route-map)#set ip precedence 5
> > R7(config-route-map)#set ip tos 12
> > R7(config-route-map)#
> >
> > Show run
> > route-map setdscp permit 10
> > set ip precedence critical
> > set ip tos 12
> >
> >
> >
> > That's it. It's a very simple relationship; if you can read hex. If
> > you can't read hex, I've posted the basic table at the end of this
> > email. Anybody that tells you that you can't set dscp in a route-map is
> > mistaken. It can be done, and there's some places where's it's the only
> > choice (such as in `ip local policy`).
> >
> > BTW, thanks Scott for pointing me in the right direction.
> >
> >
> >
> > From: Scott Morris [mailto:swm@emanon.com]
> > Sent: Sunday, November 16, 2003 1:59 PM
> > To: 'Michael Snyder'; ccielab@groupstudy.com
> > Subject: RE: routemap to set dcsp
> >
> > Ok, that would likely to something there, but why not just set ip dscp?
> > You can't do this in a route-map, but in the policy-map you could do
> > that.
> >
> > But otherwise, yet... 101 and 1100 would suffice to set the appropriate
> > bits.
> >
> > For others wondering where the heck that all came from, RFC 1349 breaks
> > things down a little differently for the 8-bit ToS field where the first
> > three bits are still IP Precedence, then the next four bits are called
> > tos bits and the last bit is called MBZ (Must Be Zero). Who ever said
> > engineers didn't have a sense of humor? :)
> >
> > As for viewing them, not really... Other than setting up an access-list
> > that permits things with a dscp value of EF and looking at the number of
> > matches.
> >
> > Scott Morris, CCIE4 (R&S/ISP-Dial/Security/Service Provider) #4713,
> > CISSP, JNCIS, et al. IPExpert CCIE Program Manager IPExpert Sr.
> > Technical Instructor swm@emanon.com/smorris@ipexpert.net
> > http://www.ipexpert.net
> >
> >
> >
> > access-list 110 permit ip any any dscp default
> > access-list 110 permit ip any any dscp 1
> > access-list 110 permit ip any any dscp 2
> > access-list 110 permit ip any any dscp 3
> > access-list 110 permit ip any any dscp 4
> > access-list 110 permit ip any any dscp 5
> > access-list 110 permit ip any any dscp 6
> > access-list 110 permit ip any any dscp 7
> > access-list 110 permit ip any any dscp cs1
> > access-list 110 permit ip any any dscp 9
> > access-list 110 permit ip any any dscp af11
> > access-list 110 permit ip any any dscp 11
> > access-list 110 permit ip any any dscp af12
> > access-list 110 permit ip any any dscp 13
> > access-list 110 permit ip any any dscp af13
> > access-list 110 permit ip any any dscp 15
> > access-list 110 permit ip any any dscp cs2
> > access-list 110 permit ip any any dscp 17
> > access-list 110 permit ip any any dscp af21
> > access-list 110 permit ip any any dscp 19
> > access-list 110 permit ip any any dscp af22
> > access-list 110 permit ip any any dscp 21
> > access-list 110 permit ip any any dscp af23
> > access-list 110 permit ip any any dscp 23
> > access-list 110 permit ip any any dscp cs3
> > access-list 110 permit ip any any dscp 25
> > access-list 110 permit ip any any dscp af31
> > access-list 110 permit ip any any dscp 27
> > access-list 110 permit ip any any dscp af32
> > access-list 110 permit ip any any dscp 29
> > access-list 110 permit ip any any dscp af33
> > access-list 110 permit ip any any dscp 31
> > access-list 110 permit ip any any dscp cs4
> > access-list 110 permit ip any any dscp 33
> > access-list 110 permit ip any any dscp af41
> > access-list 110 permit ip any any dscp 35
> > access-list 110 permit ip any any dscp af42
> > access-list 110 permit ip any any dscp 37
> > access-list 110 permit ip any any dscp af43
> > access-list 110 permit ip any any dscp 39
> > access-list 110 permit ip any any dscp cs5
> > access-list 110 permit ip any any dscp 41
> > access-list 110 permit ip any any dscp 42
> > access-list 110 permit ip any any dscp 43
> > access-list 110 permit ip any any dscp 44
> > access-list 110 permit ip any any dscp 45
> > access-list 110 permit ip any any dscp ef
> > access-list 110 permit ip any any dscp 47
> > access-list 110 permit ip any any dscp cs6
> > access-list 110 permit ip any any dscp 49
> > access-list 110 permit ip any any dscp 50
> > access-list 110 permit ip any any dscp 51
> > access-list 110 permit ip any any dscp 52
> > access-list 110 permit ip any any dscp 53
> > access-list 110 permit ip any any dscp 54
> > access-list 110 permit ip any any dscp 55
> > access-list 110 permit ip any any dscp cs7
> > access-list 110 permit ip any any dscp 57
> > access-list 110 permit ip any any dscp 58
> > access-list 110 permit ip any any dscp 59
> > access-list 110 permit ip any any dscp 60
> > access-list 110 permit ip any any dscp 61
> > access-list 110 permit ip any any dscp 62
> > access-list 110 permit ip any any dscp 63
> >
> >
> >
> > af11 assured forwarding (af11) bit pattern 001 010 = P1 T4
> > af12 assured forwarding (af12) bit pattern 001 100 = P1 T8
> > af13 assured forwarding (af13) bit pattern 001 110 = P1 T12
> >
> > af21 assured forwarding (af21) bit pattern 010 010 = P2 T4
> > af22 assured forwarding (af22) bit pattern 010 100 = P2 T8
> > af23 assured forwarding (af23) bit pattern 010 110 = P2 T12
> >
> > af31 assured forwarding (af31) bit pattern 011 010 = P3 T4
> > af32 assured forwarding (af32) bit pattern 011 100 = P3 T8
> > af33 assured forwarding (af33) bit pattern 011 110 = P3 T12
> >
> > af41 assured forwarding (af41) bit pattern 100 010 = P4 T4
> > af42 assured forwarding (af42) bit pattern 100 100 = P4 T8
> > af43 assured forwarding (af43) bit pattern 100 110 = P4 T12
> >
> > cs1 class selector codepoint 1 (precedence 1) 001 = P1 T0
> > cs2 class selector codepoint 2 (precedence 2) 010 = P2 T0
> > cs3 class selector codepoint 3 (precedence 3) 011 = P3 T0
> > cs4 class selector codepoint 4 (precedence 4) 100 = P4 T0
> > cs5 class selector codepoint 5 (precedence 5) 101 = P5 T0
> > cs6 class selector codepoint 6 (precedence 6) 110 = P6 T0
> > cs7 class selector codepoint 7 (precedence 7) 111 = P7 T0
> >
> > ef expedited forwarding bit pattern 101 110 = P 5 T 12
> >
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