It matches also on PLP, not just forwarding-class.. Since PLP is just one bit... why not use it is as a flag for rewriting?
'1' = rewrite '0' = no rewrite I think you can effectively do that.... Chris Evans wrote: > First of all please forgive me if I cause confusion on this and let me know > if I can clarify things more.. > > I come from a Cisco world and am learning JUNOS. I have a question in > regards to CoS markings on packets. In Cisco devices I can modify Layer2 or > Layer3 CoS header information INGRESS an interface. From my reading in > Juniper Devices you can only write that information EGRESS an interface and > it comes from the 'rewrite-map'. > > With Juniper devices you apply an input firewall filter that matches the > traffic and then you define it to a forwarding class. Traffic is then > forwarded through the device and once it reaches its egress interface using > the rewrite-map it marks the packet CoS information based on the > forwarding-class the packet was defined to. Also as we know, if filters > aren't applied to force traffic forwarding classification the 'classifier' > map is used to correlate the CoS markings to forwarding classes by default. > We also know that if a rewrite-map isn't defined the traffic passes out and > interface unmodified. > > > Here's my question. Say I have a router with 3 interfaces, 2 interfaces are > input and 1 output. Interface #1 and #2 are input and #3 would be output. On > interface #1 I want to mark the traffic as its currently unmarked and I want > it marked to DSCP EF(46). I have to apply the firewall filter and define > this traffic into the expedited forwarding class. To make traffic egress of > the router have this marking I have to also apply the dscp rewrite-map on > interface #3. On interface #2 the traffic is already marked to DSCP43. As I > do not have a firewall filter applied, the default classifer map kicks in > and maps the DSCP 43 traffic to expedited forwarding class as well. Once > this traffic exits the router out of interface #3, the rewrite map that had > to be defined for interface #1 will rewrite this traffic to DSCP 46, > overwriting my original markets. Now I cannot differentiate the traffic > further on in the network. > > > I see this is as a big limitation. Are there workarounds that I'm missing? > > > Thanks > > BuckWeet > _______________________________________________ > juniper-nsp mailing list juniper-nsp@puck.nether.net > https://puck.nether.net/mailman/listinfo/juniper-nsp > ------------------------------------------------------------------------ > > > No virus found in this incoming message. > Checked by AVG - http://www.avg.com > Version: 8.0.173 / Virus Database: 270.7.5/1706 - Release Date: 10/3/2008 > 6:17 PM > > _______________________________________________ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp