[j-nsp] Understanding DPC Cards
Nilesh Khambal
nkhambal at juniper.net
Tue May 4 20:28:23 EDT 2010
On MX, you can create access-ports connected to the hosts using
"interface-mode access" with a unique vlan id assigned to the port. This is
conceptually similar to "switchport mode access" on Cisco.
With either "interface-mode access" you do not need to explicitly assign the
logical unit to the bridge-domain. It automatically gets assigned to the
bridge-domain configured with same vlan-id. For.e.g.
[edit]
lab at re0-MX960# show interfaces ge-1/1/1
unit 0 {
family bridge {
interface-mode access;
vlan-id 61;
}
}
[edit]
lab at re0-MX960# show bridge-domains vlan-61
domain-type bridge;
vlan-id 61; <<<<
[edit]
lab at re0-MX960#
With this configuration, ge-1/1/1.0 is automatically part of bridge domain
"vlan-61". Now if you want to enable routing on this bridge (RVI in Cisco),
you can configure IRB interface and assign this irb logical unit to this
bridge-domain.
[edit]
lab at re0-MX960# show interfaces irb unit 61
family inet {
address 1.2.3.4/24;
}
[edit]
lab at re0-MX960#
[edit]
lab at re0-MX960# show bridge-domains vlan-61
domain-type bridge;
vlan-id 61;
routing-interface irb.61;
[edit]
lab at re0-MX960#
[edit]
lab at re0-MX960# run show bridge domain bridge-domain vlan-61
Routing instance Bridge domain VLAN ID Interfaces
default-switch vlan-61 61
ge-1/1/1.0
[edit]
lab at re0-MX960#
If you add more interfaces to vlan 61 as access ports, they will get
assigned to the same bridge-domain. It will do a switching between the ports
in the same bridge-domain and will do routing to destinations outside
bridge-domain via irb interface.
When you create a trunk carrying the same vlan id 61, it will also become
part of the same bridge domain.
[edit]
lab at re0-MX960# show interfaces ge-1/1/2
unit 0 {
family bridge {
interface-mode trunk;
vlan-id-list [ 61 62 ];
}
}
[edit]
lab at re0-MX960#
[edit]
lab at re0-MX960# run show bridge domain bridge-domain vlan-61
Routing instance Bridge domain VLAN ID Interfaces
default-switch vlan-61 61
ge-1/1/1.0
ge-1/1/2.0
[edit]
lab at re0-MX960#
You will need a bridge-domain configuration for the vlan-ids configured on
the trunk port to instantiate the switching of that vlans in the forwarding
table. In the above configuration, vlan id 62 does not yet have the
bridge-domain associated with it, so the trunk is not yet enabled to carry
its traffic.
[edit]
lab at re0-MX960# run show bridge domain bridge-domain vlan-62
[edit]
lab at re0-MX960# set bridge-domains vlan-62 domain-type bridge
[edit]
lab at re0-MX960# set bridge-domains vlan-62 vlan-id 62
[edit]
lab at re0-MX960# commit
commit complete
[edit]
lab at re0-MX960# run show bridge domain bridge-domain vlan-62
Routing instance Bridge domain VLAN ID Interfaces
default-switch vlan-62 62
ge-1/1/2.0
[edit]
lab at re0-MX960#
An access port can technically receive both tagged and untagged packets from
the host but it will only send untagged packets to the host connected to
port. A tagged port can send and receive only tagged packets. You can
configure a tagged port with a "native-vlan-id" for it enable receiving
untagged packets. It is somewhat similar to Cisco, where all untagged
traffic is assigned to vlan 1 by default and can be configured to a
different vlan if needed. When you configure native-vlan-id, all the
untagged traffic is treated as being received over the vlan configured as
native vlan.
[edit]
lab at re0-MX960# show interfaces ge-1/1/2
native-vlan-id 62;
unit 0 {
family bridge {
interface-mode trunk;
vlan-id-list [ 61 62 ];
}
}
[edit]
lab at re0-MX960#
Hope this helps. I have seen other replies providing the information about
XDPC and RDPCs as well as flexible-ethernet-services so do not want to
repeat it here.
Thanks,
Nilesh.
On 5/4/10 4:01 PM, "Martin Levin" <martin.levin at molndal.se> wrote:
> I'll try to help... We also run MX and EX.
>
> So, first off. MX and EX are not even remotely related in respect to
> what they can and can not do. The MX is a L3 box with L2 capabilities,
> the EX is a L2 box with L3 capabilities.
>
> So, vlans in an MX are not global (at least not necessarily). This means
> you can have the same vlan id on different ports without them being the
> same service (this may be a bit unclear, I apologize if that is the case)
>
> Encapsulation flexible-ethernet-services gives you the opportunity to
> use different encapsulation on different units (i.e vlan, mpls, vpls and
> so forth).
>
> vlan-tagging enables support for reception of singel tagged ethernet
> frames. If you want double-tagged it's stacked-vlan-tagging or if you
> want the option of doing both on the same physical port it's
> flexible-vlan-tagging.
>
> If you intend solely to terminate a vlan in a L3 interface you would
> simply state it like this.
>
> ge-0/0/0 {
> encapsulation flexible-ethernet-services;
> vlan-tagging;
> unit 0 {
> vlan-id z;
> family inet {
> address xx.xx.xx.xx/yy;
> }
> }
>
> If you want the option of bridging several interfaces together and
> simultaneously have a routable interface enabled it get's a bit more
> complicated. Basicly you have to set up a bridge-domain and then an
> routing-interface (interface irb) on it.
>
> //Martin
>
> On 2010-05-04 23:05, Paul Stewart wrote:
>> Hi there..
>>
>>
>>
>> I'm not sure if I'm asking this right . again, as I mentioned earlier - I'm
>> a Cisco guy jumping into the JunOS world so pardon me if I've missed this
>> somewhere in the docs. my translation between the two worlds is "slow but
>> steady"..
>>
>>
>>
>> Working on an MX480 that has a pair of DPC cards (DPCE 20x 1GE + 2x 10GE R).
>>
>>
>>
>> Some questions ;)
>>
>>
>>
>> Can someone give me in "simple terms" what the differences are between
>> "chassis network-services Ethernet" and "chassis network-services IP"?
>>
>>
>>
>> Secondly, on EX switches (which I'm just getting used too) we can do:
>>
>>
>>
>> ge-0/0/12 {
>>
>> description xxxxxxxxxxxxxxx;
>>
>> unit 0 {
>>
>> family ethernet-switching {
>>
>> port-mode trunk;
>>
>> vlan {
>>
>> members [ xxxxxxxx yyyyyyyy ]
>>
>>
>>
>> On the MX it seems this is quite different? I have the following:
>>
>>
>>
>> ge-5/0/2 {
>>
>> description xxxxxxxxxxxxxxxxxxxx;
>>
>> vlan-tagging;
>>
>> encapsulation flexible-ethernet-services;
>>
>> unit 0 {
>>
>> family bridge {
>>
>> interface-mode trunk;
>>
>> vlan-id-list 61;
>>
>> }
>>
>> }
>>
>>
>>
>>
>>
>> I'm sure this isn't correct J This is what I created after reading some of
>> the Juniper docs with a lack of understanding what
>> "flexible-ethernet-services" actually refers too..
>>
>>
>>
>> My goal is to have a dot1q trunk come in with a dozen or so VLAN's on it and
>> then create layer3 RVI's for them. The RVI configuration I have is this
>> (which again I know is wrong):
>>
>>
>>
>> vlan {
>>
>> unit 61 {
>>
>> family inet {
>>
>> address xxx.xx.235.34/24;
>>
>> }
>>
>> family inet6 {
>>
>> address xxx:xxx:235::34/64;
>>
>> }
>>
>> }
>>
>>
>>
>>
>>
>> Any assistance is much appreciated - thanks again to those folks who helped
>> earlier with my BGP questions.
>>
>>
>>
>> Paul
>>
>>
>>
>> _______________________________________________
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>>
>
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