Cisco 7300 Series Routers

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Bandwidth Information for Cisco 7304 Routers

Bandwidth Information for Cisco 7304 Routers

The following guidelines and restrictions are related to overall bandwidth limitations and should be considered when installing hardware into the Cisco 7304 router slots:

•Only one OC-48 Line Card can be used in a Cisco 7304 router regardless of processor.

•No more than 3 Gigabit Ethernet SPA interfaces should be used at any given time.

•In general, the Gigabit Ethernet interfaces, the OC-12 interfaces, and the OC-48 interface consume significantly more bandwidth than other Cisco 7304 interfaces. If you are installing any of these line cards or SPAs, please pay particular attention to the aggregate bandwidth of the ports on your router.

The connections from each of the router slots converge into a 4 Gbps link before they enter the forwarding engine (see Figure 1 for a graphic illustration). Although the physical bandwidth of the link entering the forwarding engine is 4Gbps, the actual throughput will be slightly less due to internal overheads. We, therefore, recommend not exceeding the 4Gbps of bandwidth. If bandwidth limits are exceeded, some network traffic will arbitrarily be dropped when the router is oversubscribed. Since these drops are arbitrary, routing updates, keepalives, and other critical traffic can be dropped.

Cisco Systems strongly recommends configuring your Cisco 7304 router to avoid oversubscribing your router. An error message stating that your router is over its maximum bandwidth is displayed the moment a piece of hardware that could oversubscribe the router is installed. It is important to remember, however, that the amount of traffic traversing the router determines whether traffic is dropped. The error message is simply a warning informing you that, if all ports on all the installed line cards, port adapters, and shared port adapters are used to full capacity, the router will be oversubscribed and packets will be lost. If some ports are installed on the router and are not being used, and the overall capacity of network traffic never exceeds the maximum allowable bandwidth for your processor, your router will not encounter packet drops due to bandwidth oversubscription.

Table 1 provide the maximum allowable bandwidth per processor, and Table 2 provides the amount of bandwidth each port on particular line card can consume at any given time. Table 3 provides the amount of bandwidth consumed by port adapters installed using the PCI Port Adapter Carrier Card. It is important to note that bandwidth consumed on ports directly on the processors does not count against the maximum allowable bandwidth as stated in Table 1.

The bandwidth that a particular piece of hardware in a Cisco 7304 router slot consumes when fully used can also be found by entering the show diag command.

Table 1 Cisco 7304 Processor and Allowable Bandwidth

Processor	Maximum Allowable Bandwidth1
NSE-100	3.2 Gbps (3,200,000 kbps)
NSE-150	3.2 Gbps (3,200,000 kbps)
NPE-G100	4.0 Gbps (4,000,000 kbps)

1 Bandwidth consumed by ports on the processors are not counted against the aggregate system bandwidth. The aggregate bandwidths given in this table are for ports on line cards, port adapter, and shared port adapters installed in the Cisco 7304 Router slots.

Table 2 Cisco 7304 Bandwidth

Hardware Interface or Card	Bandwidth Used per port
2-port or 4-port T3/E3 Serial SPA	44,210 kpbs per used port (.04 Gbps)
6-port E3 line card	34,010 kbps per used port (.03 Gbps)
6-port T3 Linecard	44,210 kpbs per used port (.04 Gbps)
OC12 POS Linecard or SPA	622,000 kbps per used port (.62 Gbps)
OC3 ATM Linecard	155,000 kbps per used port (.16 Gbps)
2-port OC3 POS Linecard or SPA	155,000 kbps per used port (.16 Gbps)
4-port OC3 POS Linecard or SPA	155,000 kbps per used port (.16 Gbps)
OC48 POS Linecard	2,488,000 kpbs per used port (2.5 Gbps)
4-port Fast Ethernet SPA	100000 kpbs per used port (.10 Gbps)
2-port Gigabit Ethernet SPA	1000000 kbps per used port (1.0 Gbps)

Table 3 Cisco 7304 Port Adapter Bandwidth

Port Adapters	Bandwidth Used per port
CT3 and CE3 Port Adapter	52,000 kbps per used port (.05 Gbps)
E1 and 4E Port Adapters	2,048 kbps per used port (.002 Gbps)
4T and 8T Port Adapters	1,504 kbps per used port (.001 Gbps)
E3 Port Adapter	34,268 kbps per used port (.03 Gbps)
Ethernet Port Adapters	10000 kbps per used port (.01 Gbps)
Fast Ethernet Port Adapters	100000 kbps per used port (.10 Gbps)
Gigabit Ethernet Port Adapters	1000000 kbps per used port (1.0 Gbps)
HSSI Port Adapters	52,000 kbps per used port (.05 Gbps)
OC3 POS Port Adapters	155,000 kbps per used port (.16 Gbps)
PRI Port Adapter	2,048 kbps per used port (.002 Gbps)
T1 Port Adapters	1,554 kbps per used port (.001 Gbps)
T3 Port Adapters	44,736 kbps per used port (.04 Gbps)
Inverse Multiplexing over ATM Port Adapters	155,000 kbps per used port (.16 Gbps)

Figure 1 Graphical Illustration of Cisco 7304 Backplane