Nortel Ethernet Routing Switch 2500 and 4500 ... - Ash Telecom

Product Information
Nortel Ethernet Routing Switch 2500 and 4500 demonstrate full
interoperability with Cisco Catalyst 6500 Series Switches
Premise: When today’s enterprise
network architects look for LAN access
technology, they want products and
solutions that not only interoperate
seamlessly with existing hardware, but
are also future-proofed. In configurations
where dual-vendor networks are
deployed, interoperability is essential in
order to ensure that both companies’
products deliver the applications and
business-enabling features in a single
network infrastructure.
Test highlights
The affordable and versatile Nortel Ethernet
Routing Switch (ERS) 2500 and 4500 Series
interoperated fully with Cisco Catalyst
6500 series switches during tests of various
multi-link, Layer 2 and Layer 3 features.
Test configuration
Within a lab environment, Nortel engineers
deployed either two ERS 2550T or two
ERS 4548GT switches interconnected to a
Cisco Catalyst 6509 switch. The Catalyst
6509 consisted of one Supervisor 720
Fabric MSFC3 PFC3BXL and one 48-port
10/100/1000 GE RJ-45 module. There
were a maximum of two connections
between switches in this three-switch
topology. (See Figure 1.)
Results and analysis
In total, four series of tests were conducted. The initial three series tested IEEE 802.1D,
IEEE 802.1w IEEE 802.1s in conjunction with the following features:
• Access Ports
• IEEE 802.1Q VLAN Tagging
• Nortel Multi-Link Trunking (MLT) with Cisco’s Ether Channel
• IEEE 802.3ad Link Aggregation Control Protocol (LACP)
The fourth test series was conducted to verify interoperability when running
multicast features.
Table 1. Nortel Ethernet Routing Switches 2500 and 4500
interoperability with Cisco Catalyst 6500 Series
VLAN (Virtual LAN)
IEEE 802.1D MAC Bridges/Spanning Tree Protocol
IEEE 802.1w Rapid Spanning Tree Protocol (RSTP)
IEEE 802.1s Multiple Spanning Tree Protocol (MSTP)
Access Ports
IEEE 802.1Q VLAN Tagging
Nortel MLT (Multilink Trunk) with Cisco Ether Channel
IEEE 802.3ad Link Aggregation Control Protocol (LACP)
Figure 1: Test set-up with Cisco Catalyst 6500
Topology
ERS 2550T
ERS 4548GT
Feature/capability
Nortel IGMP Snoop with Cisco PIM-SM
Cisco
Catalyst
6509
ERS 2550T
ERS 4548GT
Compatibility
✔
✔
✔
✔
✔
✔
✔
✔
✔
PC
PC

Series 1
IEEE 802.1D MAC Bridges/Spanning
Tree Protocol Test IEEE 802.1w 1
Engineers ran tests to validate interoperability
between Nortel Ethernet Routing Switches
2500 and 4500 and Cisco Catalyst 6500
series. 2 After interconnecting the switches via
standard Ethernet links, engineers verified
that Spanning Tree converged successfully.
Tests also verified that where there was potential
network loop, the spanning protocol was
able to break the loop in the network. When
traffic was sent from one PC to the other, tests
showed that all switches went through the
proper MAC learning process and that traffic
was being forwarded between these two hosts.
To demonstrate tagging interoperability
between the switches, engineers ran the same
test case using tagged links (IEEE 802.1Q).
Engineers repeated the same test case when
these switch-to-switch connections were
configured with MLT on the Nortel side and
Ether Channel on the Cisco side. Finally,
LACP (IEEE 802.3ad) was configured between
Nortel and Cisco switches and engineers
verified that switches went through the proper
MAC learning process and traffic traversed
between two hosts.
Series 2
IEEE 802.1w Rapid Spanning
Tree Protocol (RSTP) 3
To test RSTP (IEEE 802.1w), engineers
modified the test setup in Section 1 to run
RSTP (IEEE 802.1w) rather than regular
Spanning Tree (IEEE 802.1D) in all switches.
Test cases and results are shown in Table 2.
Test cases were repeated to test Nortel MLT
with Cisco Ether Channel and IEEE 802.3ad
Link Aggregation Control Protocol (LACP).
Results proved that, in the case of all three
Table 2. IEEE 802.1w Rapid Spanning Tree Protocol (RSTP)
Default VLAN with default Spanning Tree group when
Passed
inter-switch links are configured with access ports
Default VLAN with default Spanning Tree group when
Passed
inter-switch links are tagged, IEEE 802.1Q
Non default VLAN with non default Spanning Tree group when
Passed
inter-switch links are configured with access ports
Non default VLAN with non default Spanning Tree group when Failed 3
inter-switch links are tagged 802.1Q
switches, Spanning Tree convergence was
successful and that all switches underwent the
proper learning process except the last test case
in Table 2. Tests also showed that both hosts
sent and received traffic from each other.
Series 3
IEEE 802.1s Multiple Spanning Tree
Protocol (MSTP)
To test MSTP (IEEE 802.1s), engineers used
the same setup as Section 1 with one modification
— a VLAN default was used in all three
switches. MSTP was enabled and a single
region was created in all switches. This test
was run in five different permutations:
• A single access link between switch to
switch connection
• A single tagged (IEEE 802.1Q) link
between switch to switch connection
• MLT on Nortel side and Ether Channel
on Cisco side when links are access
• MLT on Nortel side and Ether Channel
on Cisco side when links are tagged
(IEEE 802.1Q)
• LACP (IEEE 802.3ad)
Once again, Spanning Tree convergence was
successful and all switches underwent the
proper learning process. As with the other
tests, results verified that both hosts sent
and received traffic from one another.
1 Nortel Ethernet Routing Switches support multiple VLANs in a single Spanning Tree group. However, Cisco supports
PVST (per VLAN Spanning Tree group); thus, the default VLAN 1 already belongs to Spanning Tree Group 1.
Engineers ran all these test cases using default VLAN and Spanning Tree Group in both vendor switches.
2 By default in both Nortel and Cisco switches all ports belong to VLAN 1 and Spanning Tree group 1.
3 According to IEEE 802.1w implementation, while running this feature, the switch can have only one Spanning Tree
Group. Cisco switch implementation is not compliant with IEEE. Since Cisco switches run RSTP with PVST, on
tagged links all the ports always stay in forwarding mode and therefore fail the last test case mentioned in this section.
(See Table 2.)
Test
Results
Series 4
Multicast features
In simple two-switch setups, one ERS 2500
or one ERS 4500 was connected to a Cisco
Catalyst 6500 series switch. Protocol
Independent Multicast-Sparse Mode (PIM-
SM) was configured in the Cisco switch and
engineers configured Internet Group Management
Protocol (IGMP) snooping in the Nortel
switch. A multicast server was connected to
the Cisco switch and a multicast client
connected to the Nortel switch.
In the first part of testing, engineers verified
that the Nortel switch recognized Cisco
Catalyst 6500 as an IGMP querier. When
an IGMP join was sent from the client, tests
validated that both Nortel and Cisco switches
accepted this IGMP join/report. Finally,
testing demonstrated that when the multicast
server started to send multicast data packets,
these packets were forwarded from the Cisco
to the Nortel switch and then successfully to
the multicast client host.
Ethernet Routing Switch
portfolio
The Nortel Ethernet Routing Switch portfolio
includes a broad collection of Ethernet
switching products designed to securely
deliver Layer 2 and Layer 3 connectivity for
converged networking. Nortel's VoIP and
WLAN portfolios are enabled over modular
and stackable Power over Ethernet (IEEE
802.3af) switches in a variety of densities.
The portfolio offers 10/100 and 10/100/1000
interfaces for a wide range of customer
budgets and performance requirements.
For more information, contact your Nortel representative, or call 1-800-4 NORTEL or 1-800-466-7835 from anywhere
in North America. Visit Nortel on the Web at www.nortel.com.
Nortel, the Nortel logo, Nortel Business Made Simple and the Globemark are trademarks of Nortel Networks. All other
trademarks are the property of their owners.
Copyright © 2007 Nortel Networks. All rights reserved. Information in this document is subject to change without
notice. Nortel assumes no responsibility for any errors that may appear in this document.
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