EX3200 and Cisco 2960 trunk link issue

[Jawwad_Paracha]

Dear All,

With reference to attached file, we are running this type of topology in our network environment. When I connect link between EX3200 secondary switch and 2960 switch it causes loop in the network and network devices attached to these switches starts to be unpingable.

Please help me regarding this issue.

Regards,

Muhammad Jawwad Paracha 

[mikep]

Hi,

could you please attach your configs? Which Junos version are you running on EX?

Kind Regards

Michael Pergament

[Jawwad_Paracha]

Cisco 2960

spanning-tree mode rapid-pvst
spanning-tree extend system-id
spanning-tree pathcost method long
!
vlan internal allocation policy ascending
!
!
!

interface GigabitEthernet0/1           (This connected to Juniper EX3200 Primary Switch)
 description Distribution layer Switch
 switchport trunk native vlan 100
 switchport trunk allowed vlan 1,25,30,75,100,150,350,400,450,911,999
 switchport mode trunk
end

interface GigabitEthernet0/2         (This connected to Juniper EX3200 Secondary Switch)
 description Distribution layer Switch
 switchport trunk native vlan 100
 switchport trunk allowed vlan 1,25,30,75,100,150,350,400,450,911,999
 switchport mode trunk
end


Juniper EX3200 Primary Switch

interfaces {
    ge-0/0/5 {
        ether-options {
            speed {
                1g;
            }
            802.3ad ae0;
        }
    }
    ge-0/0/6 {
        ether-options {
            speed {
                1g;
            }
            802.3ad ae0;
        }
    }
    ae0 {
        aggregated-ether-options {
            lacp {
                active;
            }
        }
        unit 0 {
            family ethernet-switching {
                port-mode trunk;
                vlan {
                    members [ AWT-Operations AWT-Trust AWT-Untrust-Core-Network Clearing-Operation DMZ EthCallCenter Finance GuestVlan ISM_ADMIN_HR Wateen-untrusted-vlan ];
                }
                native-vlan-id Native-Vlan;
            }
        }
    }

    ge-0/0/22 {               (This is Connected to int gi 0/1 on Cisco)
        unit 0 {
            family ethernet-switching {
                port-mode trunk;
                vlan {
                    members [ AWT-Operations AWT-Trust AWT-Untrust-Core-Network Clearing-Operation DMZ EthCallCenter Finance GuestVlan ISM_ADMIN_HR Wateen-untrusted-vlan ];
                }
                native-vlan-id Native-Vlan;
            }
        }
    }

protocols {        
    igmp-snooping {
        vlan all;
    }
    lldp {
        interface all;
    }
    lldp-med {
        interface all;
    }
    rstp;
}




Juniper EX3200 Secondary Switch

    ge-0/0/22 {
        ether-options {
            speed {
                1g;
            }
            802.3ad ae0;
        }
    }
    ge-0/0/23 {
        ether-options {
            speed {
                1g;
            }
            802.3ad ae0;
        }
    }              
    ae0 {
        aggregated-ether-options {
            lacp {
                active;
            }
        }
        unit 0 {
            family ethernet-switching {
                port-mode trunk;
                vlan {
                    members [ AWT-Operations AWT-Trust AWT-Untrust-Core-Network Clearing-Operation DMZ EthCallCenter Finance GuestVlan ISM_ADMIN_HR Wateen-untrusted-vlan ];
                }
                native-vlan-id Native-Vlan;
            }
        }
    }

    ge-0/0/18 {                                          (This is Connected to int gi 0/2 on Cisco)
        unit 0 {
            family ethernet-switching {
                port-mode trunk;
                vlan {
                    members [ AWT-Operations AWT-Trust AWT-Untrust-Core-Network DMZ Finance ISM_ADMIN_HR Wateen-untrusted-vlan EthCallCenter GuestVlan ];
                }
                native-vlan-id Native-Vlan;
            }
        }
    }

protocols {
    igmp-snooping {
        vlan all;
    }
    lldp {
        interface all;
    }
    lldp-med {
        interface all;
    }
    rstp;
}

Running JUNOS Base OS Software Suite [9.2-20081126.1] on Juniper EX3200 Switch

[Hedia · Accepted solution]

Hello,

You'are facing a spanning-tree issue.

RSTP from Cisco and Juniper are NOT compatible !

CISCO RSTP calculates STP per-VLAN (multiple instance).

Juniper RSTP calculates STP for all VLAN (one instance).

You should move to MSTP configuration on all switches or upgrade to 9.6 which supports VSTP.

VSTP uses RSTP as the protocol on a per-VLAN basis.

Hope it can help you.

Regards,

Hedi

[Jawwad_Paracha]

Thnx Hedia for the help, let me download JUNOS 9.6 and check for the VSTP and will let u know if any problem occurs.

Regards,

Muhammad Jawwad Paracha 

[Dominik]

Hi,

just a supplemental to Hedia's post: Cisco uses a proprietary variant of the spanning tree protocol: PVST and PVST+. This is what is causing the problem. Juniper published an excellent whitepaper that has a chapter about how to get Cisco and Non-Cisco switches to work togehter:

Spanning Tree Protocol in Layer 2 and Layer 3 Environments

http://www.juniper.net/us/en/local/pdf/implementation-guides/8010002-en.pdf

Regards,

Dominik

Message Edited by Dominik on 10-08-2009 08:35 AM

[Jawwad_Paracha]

I have upgraded my JUNOS to 9.6. Running VSTP on both EX3200 switches. Tested the secondary link too. Its working gr8. Thnx every1 for the help.