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Anav
Sarcastic Llama? Naw, Just Acerbic
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Dartmouth, NS
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Diff Serv (DSCP Marking) - 802.1p?

On a different thread we talked about having to use a managed switch to assign 802.1p QoS of 4 or greater for an IPTV application.

After noting that in the DIFFSERV settings on the netgear GS108T, the UG talks about applying CoS settings to the actual packets I ended up relooking at the USG100.

I note in the help file it talks about DIFFSERV and applying changes to packets but using ToS and DSCP marking etc...
Can someone with actual knowledge (as I make half my information up on the spot) on DiffServ and Tos and DCSP marking, please relate this to 802.1p and QoS.

I am starting to think that maybe the router can tag the outgoing packets (that it received via IPTV boxes) on to the networks (by applying the markings to the correct ougoing VLAN.

Any ideas thoughts welcome.
--
Ain't nuthin but the blues! "Albert Collins".
Leave your troubles at the door! "Pepe Peregil" De Sevilla. Just Don't Wifi without WPA, "Yul Brenner"

LlamaWorks Equipment



Brano
I hate Vogons
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Burlington, ON
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For starters check the links in here »Re: SIP BWM for Zywall USG 20W V3.00



Anav
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That sheds no light on the relationship between Zyxel DSCP and the standard 802.1p. I guess what I am asking is that can I use DSCP to mark or tag packets with 8021p 4.


Kirby Smith

join:2001-01-26
Derry, NH
Reviews:
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Digesting a rushed overview of the references yields (not unlike the digestive output of your llamas) a perception that 802.1p is a layer 2 type of QoS, and Diffserv is a layer 3 type of QoS. Layer 2 QoS imposed at the managed switch will perhaps control your router's prioritization of packets, layer 3 QoS is intended to be used over some extent of a field of routers, but only if they pay attention. I think you would have to ask your ISP about what they do with diffserv tags.

kirby



mozerd
Light Will Pierce The Darkness
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join:2004-04-23
Nepean, ON
reply to Anav

said by Anav:

I am starting to think that maybe the router can tag the outgoing packets (that it received via IPTV boxes) on to the networks (by applying the markings to the correct ougoing VLAN.

said by Kirby Smith:

I think you would have to ask your ISP about what they do with diffserv tags

From the Netgear GS108Tv2 Manuel:
An 802.1p header is inserted if it does not already exist. This is useful for assigning a layer 2 priority level based on a DiffServ forwarding class (i.e., DSCP or IP Precedence value) definition to convey some QoS characteristics to downstream switches which do not routinely look at the DSCP value in the IP header.

The KEY Phrase IMO: to downstream switches which do not routinely look at the DSCP value in the IP header

So I will go back to my original question -- what is the objective?
If I was to do something with IPTV --- my primary goal would be to distribute IPTV within my dwelling [TV in Kitchen, TV in Living Room, TV in Bedrooms, TV in Basement, TV everywhere I have stuff connect inside my LAN(vlan)] without have to rely on multiple STB's which is the primary advantage of multi-user multicasting with IP. The problem is that the PROVIDER in most cases has proprietary hooks preventing me from doing that.
--
David Mozer
IT-Expert on Call
Information Technology for Home and Business

OGalati

join:2005-08-19
Argentina

1 recommendation

reply to Anav

Click for full size
As Kirby said:
802.1p and 802.1q are L2 tags (CoS said in the other thread by Mozerd), and has nothing to do with ToS and DSCP, which are L3 tags. QoS is only a generic expression.

Despite the fact ToS and DSCP overlaps, all four kind of tags, when present in packets at ingress time, are valid criteria for the router to classify them. Some routers are able to tag packets at ingress port, so the router's classifications engine see these packets as "already tagged", thus can also use these tags as classification criteria. Other than this "ingress-port tagging", the router never can use (for classification) the tags it makes on the packet, since the tagging occurs after classification.

Once the router has classified the packets, the it can apply the policies, enqueuing and re-tagging at the egress time. "Egress" mean the traffic flowing out of the router throw wichever physical interface (LAN, WAN o WLAN). This is the reason why it's said the router can control only upstream BW, not downstream.

Check the image from my dumb, cheap ISP provided P660HW-T1v3 modem: Green boxes are classification criterion, red ones are actions to take over classified packets.

Hope this help.


Anav
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reply to Anav

Okay so what I am concluding from this discussion is that.

a. the USG series is not capable of tagging 802.1p (L2)
b. the USG series IS capable of tagging with DSCP. (L3)
c. DSCP is not related to 802.1p in the sense that in my twisted mind I could not program lets say half of DSCP or some bits and bytes in DSCP that would magically = 802.1p (in other words its not part of the DSCP tagging bits at all)
d. the netgear GS108T is exactly what I need because it specifically states changing CoS.

Hopefully you can understand my confusion when both the NetGear and USG have a diffserv section in their respective UG and the netgear talks about CoS and the USG talks about ToS and DSCP.

This quote muddied the water for me:
From the Netgear GS108Tv2 Manuel:
"An 802.1p header is inserted if it does not already exist. This is useful for assigning a layer 2 priority level based on a DiffServ forwarding class (i.e., DSCP or IP Precedence value) definition to convey some QoS characteristics to downstream switches which do not routinely look at the DSCP value in the IP header."

Reading the QoS chapter in the Netgear it does have a clear QoS 802.1p chapter but in this basic case its like all the other switches (incl GS2200 series) in that its simply for mapping an internal priority scheme (4 levels) 2:1 to 802.1p standards levels (0-7) so that the switch handles tagged packets accordingly (as the admin intends) and also what level to apply to untagged packets.
Quote: "To map 802.1p priorities to queues" unquote.

But it also states: "Use the DSCP to Queue Mapping page to specify which internal traffic class to map the corresponding DSCP value"
Meaning it doesnt apply any DSCP values and I dont see anywhere it can actually read them, but this switch much like 802.1p allows the admin to allow one to map any DSCP value to one of the four priority schemas (queues) similar to the CoS above.

At the start of the Netgear DIFF Serv chapter it states:
"The QoS feature contains Differentiated Services (DiffServ) support that allows traffic to be classified into streams and given certain QoS treatment in accordance with defined per-hop behaviors." Gobblity gook speak to me.

What one seems to have to do is the following:
1. Class: Create classes and define class criteria.
2. Policy: Create policies, associate classes with policies, and define policy statements.
3. Service: Add a policy to an inbound interface
Packet processing begins by testing the class match criteria for a packet. A policy is applied to a packet when a class match within that policy is found.

In the CLASS menu the following parameter might be germane.
IP Precedence - Matches the packet’s IP Precedence value to the class criteria’s when Enter a value in the range of 0–7. and IP ToS. Matches the packet’s Type of Service bits in the IP header to the class criteria’s when selected and a value is entered. In the ToS Bits field, enter a two-digit hexadecimal number to match the bits in a packet’s ToS field. In the ToS Mask field, specify the bit positions that are used for comparison against the IP ToS field in a packet.

So Class lets you identify the traffic of interest, policy which is next says what your going to do with that traffic.
The following section seems to indicate that this switch can actually change data packet contents (headers).
Configure the policy attributes:.
• Drop. Select this option to drop packets for this policy-class.
• Mark CoS. Enter the specified Class of Service queue number to mark all packets for the associated traffic stream with the specified class of service value in the priority field of the 802.1p header. If the packet does not already contain this header, one is inserted. The CoS value is an integer from 0–7.
• Mark IP Precedence. Use this attribute to mark all packets for the associated traffic stream with the IP Precedence value you enter in the IP Precedence Value field.
• Mark IP DSCP. Use this attribute to mark all packets for the associated traffic stream with IP DSCP value you choose from the menu.

BUT my concern now is that in a following text portion it uses wording to state that all three describes them (CoS, Precedence, & DSCP) in the same terms.
I know it only states in the CoS portion prior "insert a Cos Value" and I also know that this L2 switch cannot enter L2 DSCP parameters into the data. So I am confused...........

Violate Action. Determines what happens to packets that are considered non-conforming (above the police rate). Select one of the following actions:
• Send. (default) These packets are presented unmodified by DiffServ to the system forwarding element.
• Drop. (default) These packets are immediately dropped.
• Mark CoS. These packets are marked by DiffServ with the specified CoS value before being presented to the system forwarding element. This selection requires that the Mark CoS value field be set.
• Mark IP Precedence. These packets are marked by DiffServ with the specified IP Precedence value before being presented to the system forwarding element. This selection requires that the Mark IP Precedence value field be set.
• Mark IP DSCP. These packets are marked by DiffServ with the specified DSCP value before being presented to the system forwarding element. This selection requires that the DSCP value field be set.

So is CoS being marked mean the same as IP Precendence and IP DSCP being marked or is the COS different in that it can be inserted???

I am assuming that switch can only change parameters at Level 2, and why only CoS is noted as having insertion capability, which is what I need and thus my conclusion on the Netgear as a viable platform for what I am researching is still valid.

To mozerd, the switch would be configured as follows:
port 1 WAN incomming from the the ONT - VLAN 34, VLAN35
Port 2-X connetivity to STBs - VLAN 34 Diff Serv CoS 4
Port 8 To WAN port on USG - VLAN 35
--
Ain't nuthin but the blues! "Albert Collins".
Leave your troubles at the door! "Pepe Peregil" De Sevilla. Just Don't Wifi without WPA, "Yul Brenner"

LlamaWorks Equipment



Anav
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reply to Anav

Click for full size
Mozerd can you confirm in the Diffserv settings for policy on CoS, that you actually can input ACTUAL Cos values 0 thru to 7 (and not just the queue values 0-4 - high medium low lowest etc).

This diagram helped.


mozerd
Light Will Pierce The Darkness
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join:2004-04-23
Nepean, ON

Sorry no can do. I suggest that you phone Netgear Sales Support (408) 907-8000 and have them confirm what you need to know for the GS108Tv2



Anav
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Will do!!



mozerd
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Nepean, ON

1 recommendation

For the GS108Tv2 and using firmware version GS110TP_GS108Tv2_v5.0.5.7 I can now confirm [because I now have one of these] that in the Diffserv settings for policy on CoS, that you actually can input ACTUAL Cos values 0 thru to 7 --- the screen for that is quite extensive --- many fields to deal with -- so you would need to understand the implications mapped to what your ISP is doing.



Anav
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Good the manual stated it but best to see it. Also ClarkeNova has 24port jobbie same type and also confirmed it with jpegs and has a spare one for me to login to play with. Quite impressive as the other switch found to do this is the CIsco 2950T-24. A very nice EOL switch that can be had for about $50 on ebay. Its some QoS powerhouse but overkill in ports and worse size.

Its not that hard, make a class, assign a policy bobs your uncle!!!



mozerd
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join:2004-04-23
Nepean, ON

said by Anav:

Its not that hard, make a class, assign a policy bobs your uncle!!!

Good Luck with the settings and I hope for your hair's sake that you're RIGHT!


dnoyeB
Ferrous Phallus

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reply to Anav

You actually want a GS108T? I can't wait to get rid of mine. Its a weird device sometimes and looses its memory. I much prefer my Dlink DGS-1100. Looking for the 5-port version.

Ive used 802.1p but I haven't used the other thing with these switches yet.
--
dnoyeB
"Then said I, Wisdom [is] better than strength: nevertheless the poor man's wisdom [is] despised, and his words are not heard. " Ecclesiastes 9:16



Anav
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No want I want is for my USG 100 or 300 to be able to mark packets with 802.1p.

PS I can pay for shipping to relieve you of this stress causing item.



mozerd
Light Will Pierce The Darkness
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join:2004-04-23
Nepean, ON

said by Anav:

PS I can pay for shipping to relieve you of this stress causing item.

before you pay for shipping make sure its a GS108Tv2 or you'll be in going through withdrawal symptoms.


dnoyeB
Ferrous Phallus

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reply to Anav

what is special about the v2?



Anav
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It works, its compact and its a thing of beauty!!!
Check out the UG that comes with, BLOWS AWAY the stinky v1 iteration.


Anav
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reply to Anav

Yuckkk, fashion dud.....

JPedroT

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reply to Anav

said by Anav:

No want I want is for my USG 100 or 300 to be able to mark packets with 802.1p.

PS I can pay for shipping to relieve you of this stress causing item.

Your problem with that is that you are not bridging the vlans through the USG and I think that it can not be supported as of now.
--
"Perl is executable line noise, Python is executable pseudo-code."


Anav
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Yes, true.



dnoyeB
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1 edit
reply to Anav

That thing is much nicer. I'm liking the DLink because it looks much nicer as well. Plus it does not have a habit of loosing its memory for whatever reason. I have the v1 for sure. I'm ready to dump it. I think the board is loose. If I touch the RJ45s in the front, it tends to restart. Its going to meet a landfill sooner or later.

Still, v2 is so different it makes you wonder why they stuck with the same name!?

--
dnoyeB

"Then said I, Wisdom [is] better than strength: nevertheless the poor
man's wisdom [is] despised, and his words are not heard. " Ecclesiastes
9:16