What is the difference between 802.1Q and ISL?
802.1q encapsulation inserts a 4 byte tag into original frame and FCS (Frame Check Sequence) is re-calculated. ISL uses more processor cycles than 802.1q because of the modification of the header and recalculation of FCS.
Is 802.1Q Cisco proprietary?
Inter-switch Link (ISL) is a Cisco proprietary protocol that maintains VLAN information in Ethernet frames by encapsulating the whole Ethernet frame….7-4 VLAN Trunking: ISL and 802.1Q.
| Feature | ISL | 802.1Q |
|---|---|---|
| Supported VLANs | Normal and extended range | Normal and extended range |
| Protocol defined by | Cisco | IEEE |
What is an Ethernet frame’s trailer?
A Frame includes data to be transmitted and also a header and a trailer which contain information that the network adapters on the ethernet need to process the frame.
What is ISL used for?
Cisco Inter-Switch Link (ISL) is a Cisco Systems proprietary protocol that maintains VLAN information in Ethernet frames as traffic flows between switches and routers, or switches and switches.
What are the 5 parts of Ethernet frame?
Ethernet header contains five fields; Preamble, SFD, Destination, Source, and Type.
What is FCS in Ethernet frame?
The Frame Check Sequence (FCS) is a part of the frame put in place to verify that the information each frame contains is not damaged during transmission. If a frame is corrupted during transmission, the FCS on the frame will not match with the recipient’s calculated FCS.
What is tagged vs untagged VLAN?
VLAN-enabled ports are generally categorized in one of two ways, tagged or untagged. These may also be referred to as “trunk” or “access” respectively. The purpose of a tagged or “trunked” port is to pass traffic for multiple VLAN’s, whereas an untagged or “access” port accepts traffic for only a single VLAN.
How does Cisco ISL work?
How it works? The ISL works by encapsulating a 26 byte header and a 4 byte trailer between an Ethernet frame. The trailer is a Frame Check Sequence (FCS) on the ISL packet to ensure that it is not corrupted. The size of the ISL frame varies from 94 bytes to 1548 bytes.
What is an ISL port?
In the VSX solution topology, an Inter-Switch Link (ISL) is a layer 2 interface between two VSX peer switches. Each VSX switch must be configured with an ISL link connected to its peer VSX switch.
What is the difference between Vxlan and VLAN?
VLAN has a 12-bit identifier called VID while VXLAN has a 24-bit identifier called VID network identifier. This means that with VLAN you can create only 4094 networks over ethernet, while with VXLAN, you can create up to 16 million.
What is C tag and S tag?
In this double tagging, the C-Tag (customer tag) is the inner tag set by the customer. The S-Tag is the outer tag next to the MAC address.
What are the 6 parts of an Ethernet frame?
An Ethernet frame contains three parts; an Ethernet header (Preamble, SFD, Destination, Source, and Type), Encapsulated data (Data and Pad), and an Ethernet trailer (FCS).
What are the three main components of an Ethernet frame?
An Ethernet frame starts with a header, which contains the source and destination MAC addresses, among other data. The middle part of the frame is the actual data. The frame ends with a field called Frame Check Sequence (FCS). Preamble – informs the receiving system that a frame is starting and enables synchronisation.