06-04-2007 08:54 AM - edited 03-03-2019 05:17 PM
Hi folks,
I've some troubles using a 871 and LLQ for voice traffic in PPPoE scenario.
In my experience, to activate the LLQ QoS policy in this case I've to use a PPP multilink. But when I try to check the connection, I see a % of packet loss:
May 31 20:15:40.143: Vi2 MLP: Lost fragment 4CE (all links out of sequence), class 0.!!!!!!!!!!!!!!!!!!!!!!!!!.!!!!!!!!!!!
Success rate is 96 percent (48/50), round-trip min/avg/max = 16/16/24 ms
c871-TestPPPoE#
May 31 20:15:43.646: Vi2 MLP: Lost fragment 4E9 (all links out of sequence), class 0
My configuration:
871
---
c870-advipservicesk9-mz.124-11.T2.bin
!
class-map match-any VoIP
match ip dscp ef
!
!
policy-map Dial0_Out
class VoIP
priority 500
class class-default
fair-queue
!
!
interface FastEthernet4
description *** WAN ***
bandwidth 15000
no ip address
ip nat outside
ip virtual-reassembly
ip tcp adjust-mss 1452
speed 100
full-duplex
pppoe enable group global
pppoe-client dial-pool-number 1
!
!
interface Dialer0
bandwidth 15000
ip address negotiated
ip mtu 1452
ip nat outside
ip virtual-reassembly
encapsulation ppp
dialer pool 1
no cdp enable
ppp chap hostname <removed>
ppp chap password <removed>
ppp multilink
ppp multilink interleave
ppp multilink fragment delay 10
ppp multilink multiclass
service-policy output Dial0_Out
!
BRAS
----
c7200-jk9s-mz.122-15.T16.bin
!
class-map match-all Voip_WiFi
match ip dscp ef
match ip precedence 5
!
!
policy-map QoS_Wifi_Downstrean
class Voip_WiFi
priority percent 33
class class-default
fair-queue
!
!
bba-group pppoe BBA2
virtual-template 2
sessions per-vc limit 20050
sessions per-mac limit 3000
sessions per-vlan limit 20050
!
!
interface Loopback0
ip address yy.110.159.254 255.255.255.255
!
interface GigabitEthernet0/0.4093
description ***Test PPPoE***
encapsulation dot1Q 4093
ip access-group 101 in
no ip proxy-arp
pppoe enable group BBA2
!
interface Virtual-Template2
description ***PPPoE Test***
mtu 1492
ip unnumbered Loopback0
ip access-group 101 in
service-policy output QoS_Wifi_Downstrean
no peer default ip address
keepalive 5
ppp lcp delay 0
ppp authentication chap 7206
ppp authorization 7206
ppp accounting 7206
ppp multilink
ppp multilink fragment-delay 10
ppp multilink interleave
ppp multilink multiclass
!
For QoS point of view, I see that the policy is applied on Dia0, and packets match the policy-map.
The virtual interfaces are:
c871-TestPPPoE#sh user
Line User Host(s) Idle Location
* 0 con 0 admin idle 00:00:00
Interface User Mode Idle Peer Address
Vi1 PPPoE 00:00:00
Vi2 MLP Bundle 00:01:04 yy.110.159.254
On Vi1 no policies are applied, on Vi2 the policy-map is applied but no packets match:
c871-TestPPPoE#sh policy-map interface vi2
Virtual-Access2
Service-policy output: Dial0_Out
Class-map: VoIP (match-any)
0 packets, 0 bytes
5 minute offered rate 0 bps, drop rate 0 bps
Match: ip dscp ef (46)
0 packets, 0 bytes
<omissis>
Class-map: class-default (match-any)
1135 packets, 133181 bytes
<omissis>
Well, I've found a bug that sounds quite sinister ...
CSCsi76841: PPP Multilink Interleaving is not happening with LLQ configured
same as:
CSCdr60739 "Enabling ppp multilink on dialer makes link unusable"
It seems that Multilink ppp is not supported for PPPoE
In this case, any other solution to queue the voice traffic in the strict priority queue on 871 platform?
I've not experience on this device family, any advice will be appreciated
Thanks for your support
Regards
Andrea
06-04-2007 12:46 PM
Hi Andrea,
why don't you try without multilink and fragmentation? If you uplink speed is 256 or better, you do not need fragmentation, because the serialization delay is not large enough to cause problems.
Hope this helps, please rate post if it does!
06-04-2007 01:10 PM
Hi,
thanks for your answer. Without MLPPP it seems that the policy-map doesn't work ... I've no packets match on dia0 ...
Physically I've a fastethernet (as you can see on my config)
Thanks
Andrea
06-04-2007 01:39 PM
Hi,
I should have notice this before. Your outgoing interface is FE, hence is never congested.
If you really need to configure LLQ, you need to shape output to same speed as upload speed of your ADSL, this will create the backpressure for priority to work. The service policy is under the physical interface, not dialer. See example:
http://cisco.com/en/US/tech/tk543/tk545/technologies_tech_note09186a00800b2d29.shtml
Hope this helps, please rate post if it does!
06-04-2007 09:34 PM
Hi,
the dialer is required from my PPPoE config, and when I try to apply the service policy under the physical interface, it seems that it doesn't work (I've no packets match).
Any advice, for QoS or PPPoE config, will be appreciated.
Regards
Andrea
06-05-2007 07:45 AM
Hi,
a configuration like this could be solve my troubles?
PPPoE Client:
!
!
vpdn enable
vpdn-group 1
request-dialin
protocol pppoe
!
!
class-map match-any VoIP
match ip dscp ef
!
!
policy-map Dial0_Out
class VoIP
priority 500
class class-default
fair-queue
!
!
interface Loopback0
ip address x.x.x.x 255.255.255.255
!
!
interface FastEthernet4
description *** WAN ***
no ip address
pppoe enable
pppoe-client dial-pool-number 1
service-policy output Dial0_Out
!
interface Vlan1
description *** LAN ***
ip address x.x.x.x 255.255.255.0
ip nat inside
!
!
interface Dialer0
ip address negotiated
ip mtu 1492
ip nat outside
encapsulation ppp
dialer pool 1
ppp authentication chap
ppp chap hostname Test
ppp chap password
!
PPPoE RAS:
!
aaa authentication ppp default local
!
!
username Test password
!
vpdn enable
vpdn-group 1
accept-dialin
protocol pppoe
virtual-template 2
pppoe limit per-mac 10
pppoe limit max-sessions 32000
!
!
!
interface Loopback0
ip address x.x.x.x 255.255.255.255
!
interface GigabitEthernet0/0.23
description ***Test PPPoE***
encapsulation dot1Q 23
pppoe enable
!
interface Virtual-Template2
mtu 1492
ip unnumbered Loopback0
no peer default ip address
ppp authentication chap
!
Any advice will be appreciated
Thanks for your support
Regards
Andrea
06-05-2007 10:42 AM
Hi Andre,
for client pppoe, vpdn is not required.
You should be able to apply the service policy either under dialer0, or physical interface.
If the example I linked does not work, we should contact cisco and have it corrected or removed.
Good luck!
06-05-2007 12:56 PM
Thank you very much for your support!
Just a question: what the difference between vpdn-group and bba-group? And why for client pppoe vpdn is not required?
thanks again
Andrea
06-05-2007 01:19 PM
Hi Andrea,
some features like vpdn/pppoe where developed for the BRAS (broadband router aggregation services) set of functionality that are used by the ISP, for example vpdn allows one common infrastructure to be shared by multiple ISPs that get the ppp session forwaeded with l2tp.
The configuration for the home/small office access device is much simples and does not need all commands related to the above.
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