VPLS marking issue? - 未名空间MITBBS历史存档

VPLS marking issue?# EmergingNetworking - 热门网络技术

z*r2006-01-18 08:01

1 楼

I have a topology like
CE1----dot1q-----PE1-------MPLS cloud-------------PE2-----dot1q--------CE2
PEs run VPLS over LDP. CE1 is sending dot1q traffic with COS value 2, on the
PE1, I rewrite the MPLS EXP bit to 4 when matching COS 2. So on the CE2, what
COS value am I supposed to see?

v*n2006-01-18 08:01

2 楼

it depends on your configuration and implementation of PE2 吧？

what

【在 z**r 的大作中提到】

: I have a topology like
: CE1----dot1q-----PE1-------MPLS cloud-------------PE2-----dot1q--------CE2
: PEs run VPLS over LDP. CE1 is sending dot1q traffic with COS value 2, on the
: PE1, I rewrite the MPLS EXP bit to 4 when matching COS 2. So on the CE2, what
: COS value am I supposed to see?

z*r2006-01-18 08:01

3 楼

agree, but SP does NOT always want to provide classified services based on the
customers' COS. Different customers could have different COS for same kind of
requirement, say voice traffic. However, from SP's perspective, all the voice
traffic from different customers with different COS should be treated the
same. That's why SP might want to remark the EXP bits.
used
I thought 'set mpls exp imposition' setts both tunnel and vc labels, correct
me if I am wrong. sure vc label is not used for core

b*e2006-01-18 08:01

4 楼

label
If you are trusting cos, exp-bit will be automatically copied from cos, you
don't need to remark exp.
How did you set the VC label exp? and what is the point? vc label is not used
for switching.
So on the exgress PE side, after the
the
Not necessarily, depends what QoS mode you want, for short pipe mode, you cos
value is retained, no matter what Exp value you had along the way. For uniform
mode, cos, tunnel exp, vc exp are the same at ingress PE, if for some reason,
tunnel label changed a

【在 z**r 的大作中提到】

:
: agree, but SP does NOT always want to provide classified services based on the
: customers' COS. Different customers could have different COS for same kind of
: requirement, say voice traffic. However, from SP's perspective, all the voice
: traffic from different customers with different COS should be treated the
: same. That's why SP might want to remark the EXP bits.
: used
: I thought 'set mpls exp imposition' setts both tunnel and vc labels, correct
: me if I am wrong. sure vc label is not used for core

z*r2006-01-18 08:01

5 楼

agree, but SP does NOT always want to provide classified services based on the
customers' COS. Different customers could have different COS for same kind of
requirement, say voice traffic. However, from SP's perspective, all the voice
traffic from different customers with different COS should be treated the
same. That's why SP might want to remark the EXP bits.
used
I thought 'set mpls exp imposition' setts both tunnel and vc labels, correct
me if I am wrong. sure vc label is not used for core

【在 b******e 的大作中提到】

:
: label
: If you are trusting cos, exp-bit will be automatically copied from cos, you
: don't need to remark exp.
: How did you set the VC label exp? and what is the point? vc label is not used
: for switching.
: So on the exgress PE side, after the
: the
: Not necessarily, depends what QoS mode you want, for short pipe mode, you cos
: value is retained, no matter what Exp value you had along the way. For uniform

b*e2006-01-18 08:01

6 楼

label
If you are trusting cos, exp-bit will be automatically copied from cos, you
don't need to remark exp.
How did you set the VC label exp? and what is the point? vc label is not used
for switching.
So on the exgress PE side, after the
the
Not necessarily, depends what QoS mode you want, for short pipe mode, you cos
value is retained, no matter what Exp value you had along the way. For uniform
mode, cos, tunnel exp, vc exp are the same at ingress PE, if for some reason,
tunnel label changed a

【在 z**r 的大作中提到】

:
: agree, but SP does NOT always want to provide classified services based on the
: customers' COS. Different customers could have different COS for same kind of
: requirement, say voice traffic. However, from SP's perspective, all the voice
: traffic from different customers with different COS should be treated the
: same. That's why SP might want to remark the EXP bits.
: used
: I thought 'set mpls exp imposition' setts both tunnel and vc labels, correct
: me if I am wrong. sure vc label is not used for core

z*r2006-01-18 08:01

7 楼

agree, but SP does NOT always want to provide classified services based on the
customers' COS. Different customers could have different COS for same kind of
requirement, say voice traffic. However, from SP's perspective, all the voice
traffic from different customers with different COS should be treated the
same. That's why SP might want to remark the EXP bits.
used
I thought 'set mpls exp imposition' setts both tunnel and vc labels, correct
me if I am wrong. sure vc label is not used for core

【在 b******e 的大作中提到】

:
: label
: If you are trusting cos, exp-bit will be automatically copied from cos, you
: don't need to remark exp.
: How did you set the VC label exp? and what is the point? vc label is not used
: for switching.
: So on the exgress PE side, after the
: the
: Not necessarily, depends what QoS mode you want, for short pipe mode, you cos
: value is retained, no matter what Exp value you had along the way. For uniform

b*e2006-01-18 08:01

8 楼

The better question to ask would be:
1)cos is 0, why? 2) cos is 2, why? 3)cos is 4, why?

【在 z**r 的大作中提到】

:
: agree, but SP does NOT always want to provide classified services based on the
: customers' COS. Different customers could have different COS for same kind of
: requirement, say voice traffic. However, from SP's perspective, all the voice
: traffic from different customers with different COS should be treated the
: same. That's why SP might want to remark the EXP bits.
: used
: I thought 'set mpls exp imposition' setts both tunnel and vc labels, correct
: me if I am wrong. sure vc label is not used for core

z*r2006-01-18 08:01

9 楼

on the PEs I use mls qos trust cos, and mark the exp-bit for both tunnel label
and vc label, not just the tunnel lable. So on the egress PE side, after the
label disposition, the PE should copy the exp bits (in vc label) back to the
dot1q p bits, right?
the ce facing interface on the pe is just the cheap LAN card interface, which
is even not mpls awareness, but it DOES know mls qos.
If it marks only the topmost label, I would agree with you

QoS
are

【在 b******e 的大作中提到】

: The better question to ask would be:
: 1)cos is 0, why? 2) cos is 2, why? 3)cos is 4, why?