Juniper Networks 10.4 Figure5: Bridging Network with MX Series Routers, ExampleScenario

Figure5: Bridging Network with MX Series Routers
Thethree routers each have a series of hostson their Ethernet interfaces, as well as
aggregatedEthernetlinks between them. Router2 and Router 3 are linked to the Internet,
andRouter 1 and Router 3 are also linked toswitches configured with a range of VLANs,
asshown in the figure. Because the VLAN tags are important, the routersrun Multiple
STP(MSTP)on the links connecting them to prevent bridging loops(Rapid STP, or RSTP,
doesnot recognize VLAN tags and blocks ports without regardfor VLAN tagging).
ExampleScenario
Thenetwork administrator wants toconfigure these links and devices so that:
•Thesix Gigabit Ethernetlinks between Router 1 and the other routers(ge-2/ 1/0through
ge-2/1/5)are gathered into two aggregatedEthernet (AE) links mixing bridged traffic
fromthe VLANs. AE1 will consist of the first three links and AE2 will use the last three
links.The same approach is taken for the links on Router2 and Router 3.
•TheGigabit Ethernetlinks from Router 1 to the customer devices(ge-2/2/ 1 and ge-2/2/6
)will be bridged and include VLAN tag100 on ge-2/2/ 1 andVLAN tag 200 on ge-2/2/6.
Theother two routers, Router2 and Router 3, also have two portsconfigured to handle
VLAN100 on one port (ge-2/2/2) and VLAN 200 on the other (ge-3/3/3).
23Copyright© 2010, Juniper Networks,Inc.
Chapter2: Basic Layer 2 Featureson MX Series Routers